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.

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.