August 3 2011

This month has been my least active in the project so far. So naturally I haven't got very much to show in my update. I have done one useful test though: I filled the refugium and let it run for 3 weeks without any cleaning. Only with regular dosing and adding of 0.32 grams of artemia cysts every day, plus regulation of CO2 input. The refugium produced both phytoplankton and artemia for the entire period. In the end the pill shaped diatoms had taken over and were the only algae present. They seemed to do a good job of feeding the artemia. Many artemia specimens grew to 1.5 centimeters length. I did some tests at the end by letting the refugium pump run for 15 minutes. I could then see 0.5 to 1.5 cm large artemia being caught by anemones, hydroids, soft corals, and even brittle stars. The "green water" concentration problem did not occur this month. But the display tank got slightly brownish from diatoms.

Mimachlamys varia

Variegated scallop (Mimachlamys varia)



This is the feeding ring where I add 0.32 grams of artemia eggs daily.


A jar of tank water with artemia and algae.


The growth conditions for artemia must be good since some reached up to 1.5 cm in the 3 weeks I dosed them.

Display tank animals

Here are some pictures of what the display tank animals look like now. The one that has grown the most is the oyster, disregarding very small animals like barnacles and post horn worms, of course. Other than that I can't say that I am absolutely sure that animals have grown significantly. There have been some deaths too. A few sea squirts have perished, amongst others.

Alcyonium digitatum

Dead man's fingers (Alcyonium digitatum). I have around 6 small colonies of these. I can't conclude that they have grown, but I believe some have had a little growth. I don't think any have died. To the left in the picture you can see a tiny clam. Such small clams are popping up in various places. I am not sure if they are offspring from clams in the tank, if they come with the water changes, or if they have been there all the time. The brittle stars, Ophiothrix fragilis in this case, seem to be doing well. Lost arms are quickly being regenerated.

Ascidia virginea

Sea squirts (Ascidia virginea). I think some speciemens have grown a little, but not these two, they are pretty much the same now as when I caught them. But they look healthy.

Ascidia virginea

Another Ascidia virginea specimen.


I have 3 colonies of these colony forming sea squirts. They are probably in the genus Botryllus. Growth rate is uncertain yet.

Halichondria panicea

This sponge could be Halichondria panicea. I have two specimens. I don't know if they have grown, but they have changed color from grey with a hint of green, to more yellow. It seems to be in good condition, certainly not mudded down. You can see that the sponge got its shape by growing around worm tubes.

Halichondria panicea
Mytilus edulis

Mussels (Mytilus edulis). I have not measured them for growth yet. Will do soon.

Sea squirt

I haven't managed to identify this species of sea squirt.

Ciona intestinalis

Sea vase (Ciona intestinalis). I have lost one of these, but the rest seem to do well.

Ascidia mentula

Sea squirt (Ascidia mentula). This one has changed its shape a little.

Ascidia mentula

Sea squirt (Ascidia mentula), with an unidentified anemone growing on top.

Actinia equina

Beadlet anemones (Actinia equina), growing on the shell of a horse mussel (Modiolus modiolus). Notice the small mussel on the shell of the large one. It is one of the newcomers that are appearing in various places.

Ostrea edulis

Oyster (Ostrea edulis). This is the animal that has grown most in the display tank. You can see the growth area as the wide white rim with no algal growth on it.

Mimachlamys varia

Variegated scallop (Mimachlamys varia). And a little fresh mussel in front.

Plans ahead

First of all I want to start freediving. Hopefully there will be a lot of that over the coming months. I really hope to find some of the animals that I am missing in my display tank. Second, I need to find a way of marking and measuring the display tank animals so I can see how much they grow. It is really no use to have such a test project without measuring. I have some plans for how to do this without disturbing the animals. Third I hope to do some serious tests with the artemia now. I want to measure the feeding rates when artemia production is in place. I also want to introduce more anemones to the aquarium, since these feed on zooplankton. I may need more flow in my display tank, so maybe I'll install a new pump and/or a UV filter.

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