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, 7 July 2012

Lighting Updates

The search for solutions to getting enough light in the tank continues. The light panel fitted last year does not seem able to meet the needs of many of the plants typical of a south coast shallow rock pool. Whilst red algaes, particularly fine ones, seem to thrive, macro green algaes simply do not.
Crusting pink coralline algaes do well, but branching ones are stunted.
Green hair algaes are a nuisance unless heavily grazed by snails.

Recently I trialled a 50W LED floodlight, supposedly equivalent to a 500W halogen lamp. It falls far short of expectations! I built a new hood to allow the installation of 8 of these if the 1st seemed adequate for purpose - but at £65 each will probably not buy more.

A few days ago I also tried 6 no. cool white 10W LED downlights. These too disappointed.

50W floodlight only

plus the 6 no. 10W LEDs

Plus the red and blue LEDs in the light panel

Now the white LEDs in the light panel have kicked in too

Images were taken with a Canon 5D Mark 2 using a 50mm f1.4 lens at f2.2, 1/60th second at ISO 400

That, for anyone who isnt into photography, indicates that light levels are really low.

Sunday, 20 May 2012

50W LED floodlight

In my seemingly endless search for practical and cost effective solutions to lighgting the aquarium I have tried many different things. My latest experiment will be using a 50W LED floodlight purchased through Amazon for £69.99 (free P&P).

According to the manufacturers description this light is equivalet to 500W halogen, at 'Cool White' a temperature of 6000 - 6500K is good for aquarium viewing and at over 4500 lumens it packs some punch. With an exterior grade housing it will be safe to hang over the tank - looks pretty good so far.
Whilst an (almost?) identical unit can be purchased for around £35 direct from Hong King on EBay, postage at £18 makes this significantly less attaractive. Buying though Amazon does give a certain peace of mind in the event of the unit not living up to expectation or breaking down.

If this lamp passes muster I'll be buying either 3 or 5 more to supplement my Light Panel.

10th June update.....

Unfortunately the lamp was 'warm'. Around the 3000K temperature which is utterly useless to me. I returned it over 2 weeks ago and have yet to either receive a replacement or an indication if they do actually sell a 'cool' lamp (6500K) as advertised or if they dont have a clue what colour temperature even is!
Getting a bit cheesed off!


Todays water temperature at Kimmeridge Bay is a rather cool 11.5C. How important is it to try to keep a native aquarium at a similar seasonal temperature to that found naturally? Most native reefkeepers will settle for an average mean stable temperature. I have usually aimed for 16C, but in the middle of summer this is both expensive and difficult to acheive.

My old chiller seemed to pack up a few months ago. The  reservoir seemed to require almost daily topping up and the unit seemed ineffective. So I found another chiller and yesterday I flushed it out and connected it up. Its a different model from the last one. Same manufacturer but instead of 2 coils it has at least 3 with an additional 'water in' and 'water out port' which seems to circulate reservoir water. Blowing through the 'water in' port didnt produce any flow from the 'water out' port indicating that 'water in' filled the reservoir. Perhaps chilled water served at point of use passed directly through the reservoir?
Anyway - I switched the unit on and began to fill the reservoir. When I reached about 2/3rds of the way to the overflow height the 'water out' port began to pump out. I connected it to the 'water in' port to recirculate it using 10mm Speedfit fittings.
The remaining 3 pairs I connected together to maximise contact time for the pumped aquarium water. The return water is markedly cooler than the tank temperature so its certainly chilling effectively.
However, the new unit has no thermostat. Obviously some form of temperature control needs to be installed and I settled for an STC 1000 at a cost of only £26. With the probe in the display tank - or maybe the 1st stage settlement tank I can use it to control the chiller.

Current aquarium temperature is 13.5C. Warmer than local sea temperature, but still uncomfortably cool when up to my armpit in the tank!

Late summer sea temperatures at Kimmeridge reach a balmy 18C. How practical it will prove to attempt to mimic natural fluctuations remains to be seen. I suspect it will prove too arduous a chore and I will settle again for a mean of about 16. However, it occurs to me that natural cycles are triggered by temperature (amongst other factors) and we should try to replicate this in some way.

edit: 21.05.12 Temperature now 12.3C. Chiller working very well indeed. I fitted the new controller, and its very easy to set, so with reminders I may be able to adjust it say 4 times a year to replicate local sea temperatures.
To suit native reefs a monthly temperature programme would be a rather useful upgrade.....

Wednesday, 16 May 2012


Its been about a year and lighting remains an issue. The LED light panel looks good - but simply doesnt produce enough light for shallow water seaweeds unfortunately. Whilst a considerable improvement on flourescents I am struggling to get anywhere near the amount of light I think I need.

New domestic LEDs are considerably better than those on offer a year or so ago and I'll be adding a few to the light panel to beef things up a bit. Keeping wracks remains an elusive goal. They are fine for a few weeks, but have disappeared over the winter, as have many other green macroalgae species. Red macroalgaes are fine - but green and red filamentous algaes are a nuisance, possibly exacerbated by the lack of grazers due to starfish predation. Perhaps the trend can now be reversed with the removal of the starfish and the introduction of new snails.

Encrusting coralline algae is good, especially on the front of the tank where periodic removal of green algae has eliminated competition. Branching coralline algaes are smothered by hair algae at present.

I'll be watching closely for signs that snail grazing improves overall diversity within the tank, if, as I suspect, it proves to be a major factor, perhaps other macroalgaes will make a comeback.

Tuesday, 15 May 2012

May 2012 Update

OK - its been a while, and there has been a flurry of activity recently what with the good weather and all. Firstly the spiny starfish has eaten everything in the tank that it could catch and algal growth has rocketed smothering every surface to the extent that the front of the tank grows over in a few days.

Today he went to his new home at the Bournemouth Oceanarium.

About 400 snails were introduced over the weekend and have already made great progress in cleaning up. A few more may be needed to get things the way they should be though. No limpets survived the starfish ravages and next trip will hopefully furnish a few.

Today saw a large water change - the 1st in 12 months. Water has remained good over the year despite frequent feeding with NO3 at below 5ppm. A yellowish tinge has been noticed however and a change was long overdue. It seems apparent that the live sand bed does assist in the nitrogen cycle and the experiment can be judged successful by my standards anyway.

Water changes will now be carried out at more regular intervals. The introduction of fresh seawater has many benefits - mineral replacement, plankton introduction and simply the exporting of 'aged' tankwater from the system for a start.

Only 2 2-spot gobies remain. They fall easily to anemone predation. An edible crab about 3" across the carapace and a similar shore crab are often seen. They came in as tiny juveniles and have grown to this size from around 10mm in a year.

The wrasse's and mullet are doing well, growth has been strong and no mortality has been noted.

Snakelocks anemones are doing very well but beadlets have been shrunk. New water usually revives them tremendously. I'll keep an anxious eye out for them. An apparent 'Daisy Anemone', Cereus pedunculatus has appeared in the left hand corner in the sand. It looks similar to a tropical 'mushroom' soft coral.

Thursday, 12 January 2012


Its been a while since my last update and quite a lot has happened.

The spiny starfish has basically decimated the molluscs, it has lived up to its reputation as a voracious predator and wiped out the cockles, clams, mussels and snails. A few limpets still hang on - but otherwise the display tank is a mollusc free zone.

This has had a dramatic effect on the plant life, however, at the same time a failure in the power packs to the lights has resulted in a progressive, but imperceptible decrease in illumination. Hair algae has multiplied, as has green microalgae. With no grazer these green algaes have smothered many surfaces. Higher algaes have suffered and coralline algaes have been inhibited.

The loss of bivalve filter feeders has allowed phytoplankton to bloom and water clarity has suffered as a consequence. However, water quality - as far as nitrogenous compounds is concerned - has remained high. Nitrogen remains in the food chain and doesnt seem to end up as nitrates in the water column. No water changes have been carried ou since the tank was created.

This weekend wil see the spiny starfish released and a couple of hundred snails introduced. A 50 gallon water change will be effected and another manual removal of algae will be carried out. The lights have been repaired - the difference is astonishing. It was only by looking at old photographs that I was able to detect that the lights had decreased in intensity, because the drop-off was so slow it simply wasnt noticed. I didnt expect a fall off, as I would with flourescents, so didnt look for it. My fault.

I allowed the strafish to carry on with its rampant feedimng to see what the effects of snail predation might be in an enclosed enviroment. The lights failing has rather spoiled the experiment - but I am still of the opinion that snails and other grazers have a vital role in determining the vegetation of rocky shores. However, I want my tank to look pretty again, so the starfish must go and ruthless grazing will be the regime again.

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.