Native marine aquaria are pretty scarce. Little information exists on how to be successful in maintaining healthy coldwater marine systems in domestic aquaria.

Hopefully this record of my failures, triumphs and ideas will assist others interested in keeping some of our fascinating, beautiful and often little known sea denizens in aquariums.

Saturday, 10 September 2011


Whilst the animnals we are likely to keep in a native marine reef are, by and large, very easy to feed. Some care does need to be taken.
Heres a brief list of the foods I have tried:
Frozen artemia (brineshrimp) is taken by just about everything, is easy to store and readily available for little cost. Perfect for 2 spot gobies, small mullet, prawns and beadlet anemones. Very small wrasse will probably ignore it if there is sufficient live food in the tank but as they grow larger they will supplement their diet happily with all manner of foods.
Frozen krill is less popular. Whilst most fish will take it. all too often they will spit it out again. Anemones are less fussy.
Frozen chopped cockles and mussels will be taken by mullet, but wrasse seem less than impressed.
Frozen whole mussel, in or out of the shell is enormously popular and provides a good meaty treat. The wrasse tear it apart and the smaller fish eagerly wait for scraps. Blennies will not hesitate to dive in for a bite.
Whole peeled prawns make a good mouthful for larger fish. My goldsinny is a voracious predator of prawns of all sizes and frozen peeled prawns are an easy substitute for live.
Mullet will graze on algae, especially hair algae.
So, they all feed eagerly on a range of foods. What care needs to be taken then? Well, ensuring that all fish get enough to eat is paramount. Feeding a whole mussel a minute before adding some frozen artemia ensures that the smaller fish all get something to eat while the larger ones are busy demolishing the mussel. I often add a peeled prawn or two with the artemia which keeps the goldsinny occupied. Variety is good. Try different foods, maybe at different times.
Live foods, if freshly caught are exxcellent. Occasionally I add a couple of hundred tiny prawns to the tank. The goldsinny goes crazy for them, the survivors of the initial frenzy are hunted in the weeks that follow, which keeps the goldsinny happily occupied. However, with a mass of rocks there are many hiding places and not all will get caught.
Its essential to observe the feeding closely, you need to be able to spot any problems early on to ensure the health of the animals. Species that are unable to compete at feeding time will need to be catered for or released. Adding live copepods, rotifers and phytoplankton may be necessary if small fish, fry or pipefish seem unable to browse effectively. If they seem to spend a lot of time searchinmg for food but rarely 'bite' then its likely that there is nothing to eat. There are a number of excellent online suppliers that sell the above foods. I use and can reccommend their product and service.
Large blennies are particularly good at depriving other animals of food. Tompot Blennies are aggressive and greedy feeders and other fish will struggle to compete, occupy them with a large meaty morsal then add something for the others whilst its occupied.
If you keep filter feeders they will need an adequate supply of plankton. If you dont have any you'll need to add it regularly. All this may seem rather obvious - but its easy to let things slide and think that chucking in a regular feed will do - it wont! Observe feeding closely, give them variety and interest, and keep an eye out for those struggling to compete. If you cannot feed an animal correctly - and theres no shame in admitting it - let it go.

Friday, 9 September 2011

'Sand Filter'

Although not really a filter in the conventional meaning of the word sand can play a vital role in water quality. This post in an extension and revision of previous posts that tentatively explained the importance that I gave to live sand as a filter in the aquarium. I feel I am closer to explaining why I feel sand is so useful. Hopefully this post will clarify.
Sandy shores are very different to rocky shores in basic ecology. There is no primary producer on a sandy shore except perhaps for seaonal diatom blooms on more stable surfaces or eelgrass beds. Food supplies are either plankton available for filter feeders such as cockles, or detritus. The fauna can be roughly split into three categories according to size.
  1. Macrofauna - Cockles, lugworms, crabs etc. Animals over 1mm.
  2. Meiofauna - animals smaller than 1mm larger than 0.05mm
  3. Microfauna - animals smaller than 0.05mm

Almost all of these animals are infaunal - they live within the sand. The vast majority are detritivores. Within the meiofauna alone there are 22 known Phyla! The amount of biomass is heavily dependant upon the particle size of the sand or mud. The finer the particle the greater the number of animals. Coarse grained sands are practical deserts, highly oxygenated but relatively devoid of life. Very fine sands are teeming with life even though only the top few centimetres are oxygenated and are often anaerobic below 80mm or so.

It follows that very fine sands, rich in meiofauna and microfauna can be effective at consuming uneaten food, fish and mollusc waste and decaying plant matter. This consumption appears to have a net reduction effect upon the nitrate levels as opposed to more conventional mechanical filtration heavily geared towards mineralisation (the conversion of organic compounds to inorganic).

My own aquarium, with a 120mm layer of very fine 'live' sand has, so far, maintained high water quality despite no cycling. heavy stocking and frequent feeding. Its my belief that the sand has played a vital role in maintaining ammonia, nitrite and nitrate at zero. Obviously a raft of other factors have also played important roles. Lighting to allow algal growth that takes up any nutrients and minerals, high flow within the display tank to keep things moving, heavy and constant skimming to remove soluble proteins, chilling to provide the correct temperature range for native organisms to thrive and planted live rocks encrusted with different animals and plants are all undoubtably important.

Monday, 5 September 2011

Detritus and Design

If you keep a planted aquarium you will generate detritus in the form of decaying plant matter. Native algaes have cycles of growth and subsequent die-off, almost as land born deciduous plants flourish and then retreat according to seasonal cycles.
This presents significant challenges to the temperate reefkeeper. Pump intakes in particular will be prone to clogging seriously impacting on the efficiency of such items as skimmers, powerheads, circulators and especially canister filters. To a certain extent we can design the system to avoid this clogging or alternatively to facilitate the effective removal of detritus. On my 1st native marine system I built a 3 stage sump specifically to allow removal of detritus. The 1st chamber held the skimmer intake, the 2nd chamber was a lit section with a plenum and 4" of live mud to effect nitrate reduction and the 3rd contained filter pads through which return water drained before being pumped back to the system. It was rather flawed, looked OK on paper, but in practice the high flow (2 x 6400 lph Ocean Runners) blasted the mud away instantly leaving only gravel, the filter pads were continually becoming clogged causing the pumps below to be starved of water and fish were often found flapping on the filter pads having been washed through the system.
I learnt a number of lessons by the failure of this design:
  1. Weirs need to have slots cut into them to strain out fish and larger items of detritus
  2. Keep the circulation to the display tank, its generally not necessary to have 13000 litres per hour running through the sump!
  3. Use power heads or circulators to move water in the display tank instead of relying on massive return flow.
  4. Use the 1st chamber of the sump to catch detritus and move the skimmer to the middle or end chamber, there will be far less risk of the intake becoming clogged.
  5. Use natural methods of detritus utilisation rather than employing mechanical methods that will require endless maintenance.

My current system employs a slotted weir, it has proved effective at keeping even the smallest fish in the display thank whilst allowing fine vegetable matter through. Larger algal break -offs are easily removed by hand when convenient.

I use a 10 gallon settlement tank as the 1st chamber with an 1 1/2" overflow to the main sump. A layer of sintered glass filter medium on the base of the settlement tank catches and holds fine detritus where colonisation of detritivores and bacteria is encouraged. It requires no maintenance for many months at a time - if ever.

The main sump, a 3' x 2' x 2' glass aquarium contains the chiller pump and return, the skimmer and the main circulating pump. The base of the sump has a 2" layer of shells collected from the beach. This traps any remaining sediment. I keep 6 oysters in the sump to filter the water further and additionally about 30 tiny prawns have found their way here and catch any food particles that end up here. I have no problems with any of the pumps clogging and the slower flow rate of 1300 lph allows even the finest sediment to settle. A population of amphipods and copepods has colonised the sump and is presumably feeding upon the sediment. Apart from adjusting the chiller temperature and emtying the skimmer no maintenance is required for many months at a time - if ever.

Therefore, rather than engaging in detritus removal I have concentrated on utilisation. Whilst larger items are removed from the weir once a week or so, all fine particles are encouraged to settle in the 2 parts of the sump assembly. Colonies of detritivores will undergo some recirculation back to the display tank and provide food for the inhabitants but generally the low flow rate allows a stable oxygen rich enviroment for copepods and amphipods to thrive. This is as close to nature as I am able to get. In the Ocean as plankton dies and sinks to the bottom vast numbers of microfauna exist to feed upon this 'marine snow', seeded by the live sand in the display tank a similar habitat in the sump should, in theory, develope and feed upon the detritus. Soluble protein waste generated by this process can be removed by the skimmer or undergo mineralisation on the surface area supplied by the sintered glass in chamber 1 or the shells in the main sump.

I could place a few inches of live sand in the sump as well, but the sand in the main tank is probably the main filter of waste in the system. I am interested in seeing what the colonisation of the sump consists of and have elected not to introduce microfauna deliberately. As mentioned previously I hope that sponges and squirts colonise the sump, lit only by a small blue LED no photosynthesis occurs in the sump and algae cannot grow there. It is hoped that the sump will mimic a deepwater enviroment and perhaps in time will prove every bit as interesting and colourful as the main tank.

So, the design of this, my 3rd native system, has been optmised to require very little maintenance indeed whilst providing habitats for a range of organisms from brightly lit rockpools and shallow shores and also a similar sort of habitat to that found below piers and jetties. I cannot mimic the great pressures found at depth, but am unlikely to ever find deepwater specimens anyway.

I have tried out other forms of detrituis removal. My 2nd system, featured in the 1st year or so of this blog had no sump and intakes for the skimmer and chiller were in the display tank. I had endless work in keeping the intakes free of vegetable matter, the chiller and skimmer frequently became so clogged they ceased to function and the use of flourescent lighting ensured that the keeping of plants was always a battle unless I kept a strict regime of expensive bulb changing. I tried using canister filters to remove waste but once again the intakes were frequently blocked. Without constant maintenance, uncoupling the filter and washing it out, going through the immensely frustrating cycle of trying to prime it again and make it work - only to have to clean it out again a few days later, the filter simply didnt work. I spent a huge amount of time and money trying to utilise canister filters and whilst they are probably great in unplanted fish only systems I feel that they are largely a cumbersome hassle in any kind of planted native reef. However, filled with activated carbon or Rowophos they do have a place in clearing water or removing specific pollutants on a short term basis. As a long term solution to water quality they have significant shortcomings however.

The amount of detritus generated can be minimised by good quality lighting allowing algal growth to be sustained. Little is known about the life cycles of many macroalgaes and many will undoubtably die off and regrow according to the seasons even under constant lighting and temperature. It is probably unavoidable that these cycles will occur no matter what, but good lighting and flow will almost certainly keep die-off to natural cycles rather than death by unsuitable habitat.

Whatever system a native reefkeeper employs it makes for a far more enjoyable hobby if the system design allows for minimum maintenance whilst allowing the maximum number of organisms to be kept in optimum conditions with the least chance of system failure due to mechanical problems. Dealing with detritus waste is critical to system health and your own enjoyment of your aquarium. Keeping it as natural and simple as possible will go a long way to keeping native reefs a pleasure, not an irksome chore.

Friday, 2 September 2011

Skimmers and Plankton

Despite my skimmer runnung 24/7 and producing very satisfying amounts of brown gunk it appears that plankton levels are unaffected. Common knowledge has it that skimmers remove plankton - it makes sense, it seems logical and therefore it must be true!
However, after reading a post in another blog where a temperate reefkeeper in Oregon, USA, employed a skimmer to remove plankton blooms from his tank with little or no success I began to wonder if plankton is somehow 'immune' from skimmer uptake. It may be worth examining skimmer gunk under a microscope to see if it contains live plankton. I have no doubt that soluble proteins are taken up by the skimmer, but if live plankton doesnt fall under that category, if plankton does not 'stick' to air bubbles and simply passes through the skimmer unharmed - this has major implications for all reefkeepers. It explains how coralline algal growth is able to colonise tropical systems despite heavy skimming, how squirts and those tiny little tubeworms are able to multiply and cover the backs of all those rocks and how undesirable algaes are able to spread.
If skimmers do not remove plankton then they have no apparent drawbacks whatsoever. At least in any system that requires plankton to feed filter feeders such as bivalve molluscs, non-photosynthetic corals and fan worms.
Perhaps native reef aquariums, benefitting from regular re-seeding of plankton from fresh seawater under optimum conditions may find that the keeping of soft corals, bivalve molluscs and other filter feeders may prove relatively easy. If native planktonic organisms are able to reproduce and thrive in our aquariums despite heavy skimming - as appears to be the case - it seems that it may well be worth considering using a plankton tow net and specifically looking to capture plankton to add to the aquarium in the hope that desirable plants and animals might therefore be propagated.
If plankton growth is a problem, green water etc, adding more filter feeders might prove the best way to control water clarity. A full - grown mussel filters 4 1/2 pints of water a day, adding a few dozen to a geen tank might prove far more effective than upgrading a skimmer.

Sunday, 28 August 2011


Any experienced aquarist will be familiar with the need to cycle aquariums before adding any fish. The impatient novice has often learnt that its a costly and heartbreaking error to get overexcited and start adding large numbers of fish to a spanking new aquarium before bacteria levels have risen sufficiently to cope with the waste generated.
The vast number of aquariums in Great Britain are tropical, either fresh water or saltwater. We use synthetic seawater, buy inert coral sand and maybe a couple of cupfulls of same from an established aquarium, a few kilos of 'live' rock, maybe add a starter culture or, perhaps more commonly, a damsel fish ot two and monitor the Ammonia, Nitrite and Nitrate levels until more stock can be added.
If you plan to keep native marines under similar circumstances you will have to do the same. I have seen native marine aquariums with coral sand, rockery rocks and synthetic seawater. Apart from the fish and prawns nothing is wild. This set-up will take time to mature and will need cycling, a considerable amount of time, before its ready to receive more livestock and the unfortunate pioneering inhabitants may not survive the process.
However, if you collect fresh, wet sand, mud or gravel, to a depth of at least 2" for the bottom of the aquarium, use planted, fresh live rock and natural fresh seawater you can add livestock immediately. With sensible stocking levels and all the usual methods employed in maintaining good water quality it will be noted that Ammonia, Nitrite and Nitrate levels will be undetectable from Day 1.
I believe that its possible that waste products enter the food chain immediately, a vast number of organisms present in fresh seawater and sand/gravel take up uneaten food, waste and excreta etc. before it has a chance to mineralise to ammonia. What is left is easily dealt with by the more familiar bacteria and resulting nitrate is taken up by algal growth anyway. It may be that simply by access to fresh products we are able to introduce a far more diverse and dynamic microfauna to the aquarium allowing us to stock far more quickly than may be possible in tropical set ups.
If time, money, and space allowed I would like to try to gather some kind of firm scientific evidence for what is, at the moment only a theory. However, it is my experience that following the methods advocated in this blog its possible to stock sensibly as soon as the water has settled and never record any detectable nitrogenous compounds.

Seeding Tanks - Plankton

The new jetwashed Purbeck stone I added to the tank a couple of weeks ago has, in places, developed a nice growth of green algaes, grazing by snails keeps down hair algae and entero-type growth whilst some broader leaved sprouts have appeared as well as a few branching red algal growths. Its hoped that coralline algaes will eventually predominate.
To allow the maximum potential for new organisms to colonise the tank its necessary to carry out water changes, adding fresh seawater at fortnightly intervals increases the chance of catching planktonic spores and larvaes during their often brief time as plankton. Various animals and plants release spore and larvae at different times of the year.
Obviously using a plankton net with an aerated collection bucket allows far more plankton to be captured and introduced to the aquarium. A few problems have to be overcome to achieve this: open water is better, a boat is useful. A power supply to keep an air pump going - a car battery starter with a 3 pin socket outlet is enough to power a pump for 2 or 3 hours and if possible a cool box to transport the plankton on any car journey, die-off is rapid at elevated temperatures.
I keep an aerated bucket of phytoplankton to allow regular feeding of the mussels and cockles, although the aquarium has a healthy plankton population anyway, I am of the opinion that its a good idea to keep the aquarium seeded with new infusions.
The skimmer will remove a certain amount of plankton, this is inevitable and perhaps the only downside of skimming a natural aquarium. However, the benefits of skimming, in my opinion, far outweigh this drawback.
It is possible to entirely populate an aquarium using only seawater. Algaes and crutaceans, sponges and soft corals are propogated via planktonic cycles in their lives. Mussels in particular are early colonisers of new habitats, during WW2 dykes in Holland were damaged by Axis bombing flooding certain areas. When the dykes were repaired after the war and the land was pumped dry again mussels were found hanging from previously submerged tree branches and the eaves of houses! Under the right conditions this can be replicated in a captive enviroment. A refugium, with only a few rocks and some sand or gravel, will, over time develope a population of plants and animals entirely from the addition of fresh seawater. Its an interesting diversion and worthy of study as a seperate entity from the main display tank.

Sunday, 14 August 2011

More pics

The new lights shortly after installation/

Spiny starfish

Montagues Blenny

The left hand side of the tank

The Goldsinny seen here looking out of one of its caves, the sharp teeth can be seen

New Pictures

The Goldsinny chabges colour rapidly, when excited for any reason it adopts the spotted colouration seen here. In this case a mussel has been opened and dropped into the tank. The smaller corkwing wrasse often shadows the larger wrasse whilst the mullet and 2 spot gobies hang around hoping for scraps.

Here the strawberry anemone can be seen next to a mussel bed with the corkwing wrasse

Beadlet anemone

Saturday, 13 August 2011

Biological Balance

I'm not entirely sure that the title of this post is really right, but I'll plough on regardless and hope that all becomes clear. Those of us who have kept tropical marines will be familiar with the basic nuts and bolts of the Nitrogen Cycle and will be obviously tempted to assume that the same principles apply equally to native/temperate systems. However, it occurs to me that there may be some differences that might be worth exploring.
This is purely hypothesis, I would welcome discussion, either backing this up or refuting it. As such I may well ramble, I may be entirely wrong, but whatever the case I believe its worthy of discussion.
Firstly there are fundamental differences in the nutrient levels of tropical and temperate enviroments. Speaking extremely broadly it seems to be an established principle that tropical reefs are nutrient poor. I've never been entirely sure what this actually means! However, it also seems equally established that cold water ecosystems are nutrient rich. I understood this to mean that cold currents upwelling from the deep carried minerals and nutrients to the surface providing food for massive plankton growth which fuels some of the largest bioloads on the planet. Wherever these currents rise to the surface - the West Coast of South Africa, the East Coast of South America, the West Coast of North America vast numbers of fish, birds, whales etc benefit. I dont know what these nutrients are - organic or mineral? Whether the term 'nutrient' is accurate or not it is a term often heard on Nature Programmes on the television when describing the rich food chains of the places mentioned above.
Anyway - what does this have to do with native marine aquaria?
Tropical marine aquaria are geared towards nutrient export, to approach the conditions found on tropical reef crests it is obviously necessary to do so. As tropical aquaria in the UK and North America are almost certainly required to use synthetic seawater, inert coral sand and 'live' rock that has been cured (ie all dead and decaying organic matter removed) they start off with only the hardiest bacteria and microfauna to carry out the biological processes of nitrification and denitrification, phosphate reduction, detritus mineralisation and everything else. In many cases this seems to be adequate, successful tropical reefs are attainable and well documented. All seem to employ live rock and nutrient export.
Deep sand beds, filters, mineral additions, 'miracle mud', refugiums, skimming, water changes, water movement, detritus removal, careful husbandry and lighting in a myriad combinations and variations all play a part in successful tropical reefkeeping.
Temperate reefs do not have the benefit of live coral rock, many of the rocks found around our coast are impermeable, essentially inert with no buffering capability and provide no habitat for bacteria other than the surface. Likewise the sands and gravels found around our coast are often silica based, in a tropical aquarium such rock and sand would be deemed utterly useless as a substrate for carrying out the nitrogen cycle. Yet the mineralisation of organic waste still occurs effectively. It seems possible that other processes are at work here. This is where I get on to very shaky ground!
My tentative theory is that effective mineralisation is carried out in captive native systems by multi-celled organisms as well as bacterias. We dont have the vast surface areas utilised in tropical aquaria using coral sands and rocks. Whilst Nirobacter and Nitrosomas bacterias are undoubtably present in significant amounts there is simply not the same surface area for them to colonise. I notice that the sand bed of my tank, collected at low water and transported directly to the aquarium was dark just an inch or so under the surface. As it has settled and matured there are myriads of tiny tunnels throughout. Vast numbers of worms, too small to be visible to the naked eye are present. What other creatures also live in this sand? What do they eat? What processes are being carried out? Are similar organisms present in tropical aquaria? I believe that these organisms may not survive prolonged exposure to travel and collection trauma. In a native reef we are fortunate to be able to transport them alive and well by rapid transit. I believe that the presence of microfauna of many different species in a native captive reef are in some way facilitating all the biological processes necessary to effect mineralisation of organic waste to end products suitable for plant take-up.
Therefore, it seems that a fundamental difference in 'nutrient' utilisation is apparent between tropical and temperate systems. Temperate systems may well need nutrient retention within the food chain. Tropical systems are geared towards nutrient removal from the system.
Thats probably enough to be thinking about for now. I'll have more to say on such fascinating topics as detritus later.
Its low tide at Osmington Mills in 90 minutes and the family are ready to go rockpooling. More topshells are needed!

Wednesday, 10 August 2011

New Tank Update

The new lights arrived today. 45 x 10W LEDs in an attractive aluminium panel with lots of switches and fans. All very professional and impressive. I went to LedAquaReef in New Milton, I found them on EBay. Jon delivered them this morning and helped me to install them. I advised him of what I was trying to acheive and he designed the layout as follows:
5 no. red LED
10 no. blue LED
30 no. 6500K white LED
The reds offer light most useful for boosting photosynthesis and the blues balance it out a bit, without the blues its too pink. The overall effect is very natural to look at, although it is perhaps more attractive to a tropical reefkeepers eye with the reds off. All the colours are independantly controlled and additionally the whites offer 3 different switching combinations.
The light panel is easily capable of lighting an SPS coral reef and should prove sufficient to keep extreme shallow water native marine plants as found in south coast rockpools.
I've re-landscaped the tank, using about 300kG of purbeck stone originally purchased about 6 years ago for my 1st native marine tank (which burst!) and languishing in the garden for the last 5 years or so. I jetwashed it clean and placed it at the back and bottom of the tank, replacing my planted rocks above. In a couple of places the bright, almost white, 'new' stone can be seen. I'm keeping a photo diary to document the colonisation of the new rock. It will be interesting to see how quickly and in what order new species colonise it.
Purbeck stone is ideal for my reef. Its the natural rock of the area where I collect, consisting of the skeletons of marine organisms that died millions of years ago, permeable and with great buffering potential it should perform in a similar fashion to coral base rock.
Today I added 25 cockles from Poole Harbour, with the 100 or so mussels I already have in the tank they will perform an active role in filtration. I feed a cube of frozen rotifers a day to the sprat fry, it is hoped that the mollucs will benefit from this as well. I still plan to get an overhead refugium up and going to allow a constant supply of phytoplankton but in the meanwhile I have decided to place a regular order with a company called PhytoReef, they supply live phytoplankton and rotifers by mail order.
Today I found a rather attractive bright orange sponge growing on a rock as well as a possible jewel anemone. I'll keep an eye on it.
The snakelocks anemones have gron much larger - probably on a diet of 2 spot gobies. Although these fish are freqently found in the same place as snakelocks it seems that they are a rather hapless prey. Despite many hours of watching I have yet to see one actually get caught they have become fewer in number at the same time as the anemones have grown substantially larger. Perhaps they are more easily captured at night?
The Goldsinny, at about 7" long is easily the king of the tank. It has well-developed teeth and has been seen chomping on a small shore crab, although it will take krill it is most easily tempted by a frozen whole mussel in the shell. Whenever we have Moules Mariniere for tea I keep all the open shells in a bag in the freezer. I use a knife to partly open the shell to allow the fish to get inside. If you cut the shell completely in half it tends to fall flat side down with the shell uppermost, so its important to leave the two halves still attached.
All the other fish gather round whilst the wrasse feed hoping for a scrap, the Montagues Blenny dives straight in and takes a bite in typical blenny fashion.
The spider crab is behaving rather oddly. It has been seen tending its abdomen with the tail flap lifted. No eggs are visible and the larger spider crab was released months ago, but I wonder if it is gravid?
The bladderwrack has survived well under the old makeshift light panel although other seaweeds have changed colour from bright yellow green to reddish brown indicating insufficient lighting levels. The new lights should reverse that change.
I have fitted a 4.5W blue LED over the sump, I'm adding shells and some vertical piling type structure to encourage the settlement of squirts, sponges, soft corals etc. I hope that they maight be present as plankton in the water. It may be worth carrying out plankton collection trips to seed the tank further. The skimmer doubtless has removed much of the original plankton, it is producing an enormous amount of foam!
I added a couple of kilos of sintered glass to the settlement tank,, it used to be in the overhead wet/dry filter in my Amazon biotope tank and should help to trap the sediment collected and provide a more stable habitat for the organisms that feed on the detritus that will settle there.

Why Go Native?

Perhaps, as a successful tropical reefkeeper stumbling across this blog you might wonder why on Earth anyone would want to keep our own humble native fauna and flora when the tropics offer such stunning colours and diversity. As a convert from tropical to native myself I'll try and explain:
Biotope: As a native marine reefkeeper you can choose to collect only specimens, water, substrate and rock from a specific location at a set depth range. You can be sure that everything you collect will interact in some way with everything else as nature intended. For instance I collect from the south west of Britain at no more than 1.5 metres depth. On a single day of collecting I can easily find a dozen plant species and 10 fish species.
When you keep a tropical tank many of the species offered at your LFS are from a huge range of depths, locations and habitats. Soft corals from Indonesia are on sale next to Red Sea fish and Pacific SPS corals. Many will have no natural relationship to each other whatsoever.
Mortality: With the very simplest and most basic precaution it is entirely possible to collect many different animals and transport them to your aquarium with no mortality. Should they not flourish it is equally easy to recapture them and release them back to where you found them. Many of the native species are very easy to keep in any case, feeding is rarely a problem, most fish, for example, feed readily on frozen artemia or rotifer and freshly opened mussels tempt even the most finicky larger fish. It is a sad fact that for every wild tropical marine fish in the LFS many more have died during the process of collection and transit. Too many more will die in the 1st few months of captivity, through their unsuitability for home aquaria through diet or habitat requirement.
'Total Reef': It is simply not possible to aquire a sufficient biodiversity of tropical reef inhabitants unless you live next to one - in which case it will be a 'native' reef anyway! A box of Fijian 'live' rock may have spent over a week wrapped in wet newspaper before you even see it, maybe longer. Obviously many of the original inhabitants encrusting the rock have succombed. Contrast that with a 'live' rock covered in seaweeds, sponges, anemones and coralline algaes collected from your local rockpool and placed in your tank an hour or so afterwards. Almost everything will have survived, if not everything. I never get bored with watching a new rock and seeing how many different creatures show themseleves.
Its entirely possible to collect a complete range of organisms, each performing a vital role in the chain, and get them home and safe with the minimum of fuss. By using live fresh sand/gravel, fresh seawater and fresh live rock you can be confident that the tank has not just fish and seaweed - but plankton, bacteria, microfauna and microflora - everything that a natural reef needs for any kind of realistic biodiversity.
Fun!: A days rockpooling is something that just about every kid (and many wives) loves. Its immensely satisfying to find, capture, identify and then keep successfully any creature found during a days rockpooling.I always found that buying fish and corals in my LFS was an expensive and solitary pursuit - I loved it, dont get me wrong - but it doesnt compare to piling the wife and kids in the car, heading for the bach with a picnic and a wealth of buckets, nets and jars and catching our own.
Expense: Not the most important reason to keep natives, but surely an attractive one nonetheless. Bearing in mind that mortality should be close to zero anyway with native marines, even if we had to pay for them they would represent a considerable advantage over many tropical fish and invertebrates. The fact that they are essentially free, a by-product of a great family day out even, makes them almost irresistable!
The Challenge: There is almost nothing online or in book form to guide the native marine reefkeeper. Its an unwritten book and everyone who keeps natives and writes something about it is a pioneer! A grounding with tropicals is, at the moment, therefore essential to success. However, there are major and significant differences and thses may not be immediately apparent. However, if you have successfully kept a tropical reef you will certainly enjoy success with a native one - just how natural, dynamic and diverse your native reef is will prove endlessly interesting and challenging. You can be sure that few have trod the same path and much remains to be learnt.
Beauty: Whilst no one would deny that tropical reefs offer unrivalled colour and beauty, many of our own native species of fish and invertebrate are nonetheless extremely attractive to look at. Squat lobsters - crimson and electric blue, cuckoo wrasse are rainbow coloured, beadlet and jewel anemones are a match for any tropical species, branching and encrusting coralline algaes are as pink as anything tropical and both red and green macroalgaes can be fabulously lovely.
In short, native marine reefs are well worth a second look. They are inexpensive, enjoyable, interesting, beautiful and ethical to keep. For the amateur naturalist there is a wealth of knowledge to be imparted, little information is available on many of these fascinating creatures and plants, every native reefkeeper has the potential to add, in a meaningful way, valuable knowledge on our own, little known, native marine flora and fauna.

Sunday, 31 July 2011

July in Cornwall Collecting Expedition

I have just returned from a week in Cornwall collecting new specimens. I collected from four locations -
Fowey Harbour - approx 50 2 spot gobies, 1 Goldsinny.
Wallace Beach, Looe - 3 mackeral fry, 75 periwinkle, 3 juvenile Ballen Wrasse, 2 brittle star, 1 beadlet anemone.
Porth Mawgan - 14 Sprat (?) fry, 1 Strawberry Anemone, approx 100 mussels, 4 dog whelk. Treyarnon Bay - an amazing beach, fabulous deep rockpools - 1 Lesser Sandeel, 1 Shore Rockling, 3 Golden Mullet, 1 Spiny Starfish, 1 Montagues Blenny, 1 tiny Shanny, 1 Warty Anemone, 2 Sprat (?) fry.
I kept the animals for up to a week in a 60 litre 'really useful box' with an airstone and carried oput daily water changes. I fed them on frozen garlic enriched artemia. All fed well and there were no casualties! It took 3 1/2 hours to get home and there were no motalities during transit.
All are now installed in the aquarium and have settled in well. They are feeding and seem to be behaving naturally. I originally intended to collect about 6 2 Spot Gobies, but wherever I found them they occured in large shoals so I decided to collect 50. Male to female ratio is about 1:2. They were exceedingly numerous, I fished for them in one spot only and I would guess that there were many hundreds along a sea wall only 30 feet long.
I wasnt sure about the Spiny Starfish - but my wife and children loudly convinced me! If it proves too destructive I'll release it. Its about 10" across and according to all literature I could find on it is a voracious predator! I'll offer it frozen mussels and clams, hopefully that will reduce its grazing upon my live mussel beds.
I found a crab net baited with squid to be the most effective way of catching fish, all the gobies and the Goldsinny were caught using this method.
The Shanny was an unintentional catch, we caught many dozens of shanny at all locations, however, I have found them to be too destructive to barnacles, snails, hermit crabs and prawns to be desirable as captive reef inhabitants. I didnt even see it til we got back to Bournemouth, my 6 yr old son proudly claimed to have added it to the bucket! Its about 4mm long and unlikely to be a problem for a while yet.

Monday, 18 July 2011

Lighting Considerations

I am at the design stage of new lighting for the new tank and a number of considerations are becoming apparent. Tropical reef tanks largely utilise light at the blue end of the spectrum, many reefkeepers seem to use lights in the 10000 - 20000K range. Stony corals seem to thrive best under these conditions and undesirable algal growth is inhibited.
However, in a temperate reef, algae is far and away the dominant natural feature. Therefore it seems likely that warmer lights are required. Natural sunlight is in the region of 5600K. This casts a yellowish light within the aquarium that isnt as attractive as the cooler higher ranges.
If we take 'white' light at 5600K and pass it through clear water the red end of the spectrum is effectively filtered out within 15metres. It might follow, therefore that unless we are collecting plants at depths greater than 15m we need to provide full spectrum white light.
I have built a temporary light hood, its a plywood board 1600mm long by 400mm wide. I have fixed 8 no. 3 light spotlight fittings from B&Q and fitted 15 no. 'cool white' LEDs and 9 no. 'warm white' halogen lamps (supplied with the spotlights). I understand that the cool white lamps are in the region of 7500K and the warm white lamps about 4500K.
The overall effect appears very natural with a pleasing 'ripple' effect. Although designed as a temporary measure to get some light into the tank whilst waiting for new lights to be manufactured I am beginning to wonder of these may be adequate for the job. To be honest its primarily down to cost:
new LED light panel - 450 W £1000.00
my own light panel of 24 lamps, 15no. @ 7W and 9no. @ 50W has cost £480 so far. I paid £20 each for the LEDs, double the usual cost because they are dimmable. However, I can return them for double the amount of non-dimmable ones. The cost of a LED GU10 bulb is £9.00. I would need 64 to acheive the same amount of power consumption as the manufactured LED panel. At 50W equivalent output that is 3200 Watts of light into the tank!
There are pro's and cons for both. The manufactured panel has an output of light that I cannot replicate using spotlights, I simply could not fit 22 of the B&Q fittings over the tank. It has built in cooling and uses LEDs of a known fixed colour temperature. A mix of cool white, blue and red lamps of a ratio of 25:10:10 respectively, of 45 10W LEDs should be both aesthetically pleasing as well as giving light at the corect spectrum for macroalgal growth. However, if any LEDs fail I will be unable to replace them easily - each is individually soldered.
My home-made hood allows easy changing of lamps. It is likely that better, higher output lamps will be available over time. GU10 fittings are readily available and available in blue, cool white and warm white.
I could fit another 18 lamps on my hood. An extra 6 spotlights at £9.00 each (each has 3 lamps) would allow a total of 42 LED GU10 lamps at equivalent 50W output giving 2100 W whilst consuming less than 300W. A mix of cool and warm white with maybe 3 or 4 blue should come somewhere close to giving the right result. The cost would be 24 spotlights at £9.00 each and 42 lamps at £9.00 each a total of £594.00, about 60% of the cost of the manufactured panel with 2/3rd of the output, no built in cooling and a bit 'Micky Mouse'!
Obviously the manufactured panel is going to be better. Its just the outlay.
I've added some rocks with macroalgae growth and placed them under the lamps. I'll give it 2 weeks and see how they fare before making a decision.

Thursday, 7 July 2011

July 2011 Update

Its been a year since a water change was last carried out and little has changed. I switched off the skimmer a couple of months ago as no foam was being produced. The feeding has been extremely light, one small cube of artmis shrimp every 3 or 4 days.
The lights are over a year old now and the output has decreased significantly. This has caused a slow-down of macro-algal growth. As a new set of flourescent bulbs costs about £160.00 I have been looking into another alternative. I am experimenting with 'white' LEDs, a standard bulb costs about £20 for a dimmable LED in the right sort of spectrum - 5600K, non-dimmable are cheaper. The light is still a little warm and actinic flourescent T5s are needed as well. I havent been able to rig up a permanent new lighting set up on my existing tank due to a lack of time but have built a small prototype of six lamps which does create a very pleasing effect similar to halides without the heat!
So, today I have emptied the aquarium and ordered a new 1.8m L x 0.75 W x 1m wide acrylic aquarium, I'm collecting it on Tuesday from Hampton Court Flower show where it is currently forming part of a garden display. I will drill a 2" hole in the base and fit a weir which will carry the water to my old 3' tank below.
The inmates of the tank are currently in a 100 gallon cold water plastic 'roof tank' in newly collected seawater. I will move them to the sump tomorrow with all rocks but none of the sand substrate currently in a number of buckets. When the new tank is in position and plumbed in, the rocks and substrate will be introduced and a 6" layer of fresh substrate laid on top. New chalk base rock will be collected to add to the existing rock and the whole system will be topped up with further fresh seawater. Finally the inhabitants will be introduced to the new aquarium from the sump by next Thursday (hopefully!).
This weekend I will build a new hood from plywood housing around 60 LED lamps on 3 timers, the dimmable lamps will be at each end and will come on a 'soft start' programme, the centre section of 40 lamps will come on when the dimmable lamps are at full power. Hopefully this will cause less stress to the inhabitants than a sudden full-on switch on of the lamps. The T5 flourescents will come on a seperate timer a few minutes after the central section to hopefully produce something like full daylight power. I believe that strong lighting is essential for keeping shallow native marine reefs.
The existing tank will be the sump, this will house the skimmer and the return pump as well as the pump to the chiller. I will probably lay a coral sand substrate and a number of chalk rocks, this should act as a buffer for maintaining water hardness and also stabilise clacium levels. Usually I would keep this under 24 hour lighting but to avoid blocking up of the fine tubing to the ciller and also the intake of the skimmer, the sump will be dark. No algal growth should prevent the problems that have plagued my original set-up.
However, as I am such a strong advocate of some kind of refugium/algal tank as a way to naturally filter the water I will install a smaller aquarium above the new display tank with 24 hour lighting to encourage algal growth. This will be fed by the sump return pump and will overflow into the display tank. It is hoped that this will be a breeding gound for creatures that will fall into the main tank and provide zooplanton as food for the inhabitants.
Once the system has stabilised I look forward to collecting new inhabitants. Many of the creatures from last year have since outgrown the tank and have been subsequently released. The spider crab grew to a monster that decimated the hermit crabs and snails, he was released back to Kimmeridge in May. Curently only 1 corkwing wrasse reamins and 1 small spider crab that must have came as a hitcher on a rock, at 1 1/4" he is still reef safe, but will probably be sent back to the sea in the autumn. I have many anemones, both the snakelocks and the beadlet have reproduced with numerous offspring.
The addition of a sump and new LED lighting should solve the problems that the original system suffered from - deterioration of lighting strength and clogging of skimmer and chiller intakes. An overhead refugium will be an interesting development, this will probably not be possible in most set-ups but my office has a high ceiling and will allow a further tier.