Clam help

[Mr Nasty]

I need some clam advice. Last March I purchased a large Deresa clam at the LFS. He immediately took to my 125g reef opened up wide and has looked beautiful everyday until 2 days ago. At first he did not open all the way, then his mantle started to receed, now his mantle is receeded as far as it can go and he does not close his shell at night, and his body tissue looks like crap!
All of my water conditions are fine , the only thing I can think of is that my Calcium is not high enough (between 250 and 300)but if this is the case than why has he looked absolutely beautiful for the last 5 months? What about lighting? I have 2 95 watt pc and 8 so flouresent 4 with actinic and 4 with white. total of 430 watts.

 

[Agu]

I'd suspect your lighting isn't adequate and it opened wide trying to capture more light. Try moving it up in the tank, preferably under the pc's.

Good Luck,
Agu

 

[JohnL]

I've had 3 clams do this on me. In each case, they were dead the next day. Give the clam the "wiff" test and you will know right away when it is dead.

 

[simonh]

Sorry to hear about your clam. Not really sure what the cause is although I would try maintain a higher calcium level nearer 400 so the clam is growing fast.

One thing that I have wondered about deaths of totally healthy clams like yours John is whether it is due to toxic metals. I did read in Yuri Sorokin's book that with clams having a kidney they tend to buildup heavy metals and so could be used as a sign of toxic metal poloution. Maybe over time the clams buildup levels from the excess in our salt mixtures and food etc... ?

 

[DJREEF]

Sorry to hear that Mr Nasty. Unfortunately, your clam starved to death. I see you have fallen victim to the fallacies of the watts per gallon theory. As I have been preaching, light intensity is the key to success with clams. Flourescent lighting, while aesthetically pleasing, just doesn't have the depth penetration necessary to keep clams healthy long term. If you aren't point sourcing with metal halides, or HQI, or keeping your clams right at the top w/ flourescent (even this doesn't always work), your success with clams is going to be limited. Did the clam grow at all while you had it? This is the only reliable indicator that a clam is receiving enough light. If a clam isn't putting down new shell, then that ain't good. If the clam was putting down new shell and isn't anymore, then your bulbs need changing, because the spectrum has shifted. I hope this helps for the next time. Don't give up, just use the right tools.

DJ