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.

Wednesday, 24 November 2010

November observations

Snakelocks anemones have greatly increased in number through fission reproduction and appear very healthy with fully extended tentacles often tipped in purple.

Beadlet anemones have largely remained in their original positions, are usually extended and some budding of young has occurred. The aquarium seems suited to anemones.

There has been no water change for over 3 months now, it appears that the aquarium is largely self-sustaining, glass remains very clear, mortality is very low, apart from some of the mullet being eaten by anemones, the predation of snails by the larger spider crab and the demise of the smaller spider crab, it appears that all inhabitants originally introduced are thriving.

Water temperature remains at 16 C, the lights remain on a 12 hour cycle and skimming remains heavy and constant though the increase in algal growth has resulted in far more frequent cleaning of the inlet filter to keep foam production at a good level.

The aquarium remains attractive in appearance despite the red algal explosion, ideally a grazer would be introduced to keep it down, but I believe that the answer probably lies in much stronger lighting to encourage the growth of green algaes along with mineral supplements to suit the requirements. Wrack growth is very slow although other species seem satisfied.

Long term, when finances allow it appears that a larger, drilled tank with halide lighting and a sump to protect the skimmer from clogging of plant growth is going to be desirable. A deep sand bed would be something I would like to trial. 2" is not enough to allow the growth of populations of organisms that could contribute to the food chain.

I have noticed that the water in the chiller needs regular topping up, if left for too long the chiller becomes far noisier and hotter. I try to keep an eye on this, I have heard of chillers catching fire before - 'Southern Aquatics' in Creekmoor in Poole was set ablaze by an aquarium chiller and I have to wonder if a lack of water in the chiller reservoir may have been a factor?

Red Algae Explosion!

I've been pulling out large amounts of a red, branching, very fine hair algae that appears to have no grazer within my aquarium and is smothering all my other algaes. I've been unable to identify it. When it 1st appeared a month or so ago I thought it was rather attractive, but it has now become a pest!

Macroalgae growth has been pretty good, with Oyster Thief (Colpomenia peregrina) growing up to 7" across and having to be removed, further smaller specimens are being allowed to grow.

Dictyota has sprouted in a couple of places, but suffers from red algal smothering.

Wrack growth is very slow - probably due to mineral defficiency. Cystoseira remains healthy with many attractive bright turquoise shoots.

A probable Calliblepharis has propagated on the glass, an attractive red macroalgae that unfortunately chose to grow next to one of the powerheads.

Coralline algaes suffer from smothering by the red hair algae, but where exposed to light remain healthy.

It is possible that lowering the temperature will have an effect on the red algae, but its my belief that the light levels are too low for the green algaes to out-compete it.