have a 26 gallon nano with a crocea (2) actually.
The first I have had for a little under a year. Over the last month or so, the mantle has shrunk and it seems now the mantle is not opening.

I have compact florescents. Is this slow starvation? I have done and checked the usual tests and water changes....

The clam in question is one the bottom middle section. Now it looks like this..(second pic)-bottom center of picture

1. attage is 65 Watts Daylight and 65 wat actinic however, they are the Orbit Compact Florescent bulbs, one of them is actinic and the other daylight for 3.5 years now.
2. Parameters: Salinity 1.020, pH 8.0, nitrate trace, phosphate 0, alkalinity is 2.5, calcium is 250mg.dl, (no nitrite or ammonia)
3. Test kits are the Aquarium systems brand
4. All corals are fine. The bubble deflates towards the end of the day.
5. 10 gallon (2X5 a month using Oceanic Sea Salt from Petco) - 2.5 cups of salt in 5 gallons of RO water from Crystal Rock Water Co, Watertown CT dissolved overnight at salinity of 1.025 or so @temp at 80 degrees F.

Tank running for 3.5 years.

Note: The entire experience is one of change.....some corals do great and others not so great. For instance, the kenya Tree coral did ok for 3 years, never great until three months ago, when it had a huge growth spike??? The toad stool coral was 1.0 inches tall, now is 10 inches tall and huge...

I did notice when I used the aquastick three weeks ago to anchor the brain coral and the gorgonian, the skimmer went wild d/t to the anti-surface tension organic molecule in the glue....TERRIBLE!!

When I get the new supply of water this Thursday I plan on another 10 gallon water change gradually. Thats almost 50% water change.

The sea hare in the picture dissappeared two weeks ago when we went on vacation for a week, Cant seem to find it anywhere in the tank.


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Experienced Reefer
i think your sg and pH are just a little low...we have a crocea in our tank but we have it placed high in the rockwork with MH...from the info i got about them, they are one of the harder species of tridacnid clams to keep, needing about 5-6 watts per gallon, high calcium levels (400+) and lack of any animals that may pick at it...

65 watts is pretty low light levels for that type of species...a squamosa may be ok since the light needs arnt as high but you may want to consider placing the clam higher for the mean you have any plans on upgrading your lighting soon?


Hello, thanks for your reply.

I have switched to MH right after I fugured out the problem(with the help of other websites) and got four clams, three crocea and one squamosa. All seems to be well except for the usual issue I have with bryopsis!!! It is very resilient!!

I have also installed a refugium in the last two weeks with Chaeto, so lets see what happens

Here is a shot of the tank from the last week.



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