Why are my clams dying?

[dragon_wrasse]

A tridanca maxima clam that I've had in my tank for over 4 years died suddenly about a week ago. It looked fine the day before, and the next morning the mantel was pulled completely into it's shell.

Tonight I found the byssal gland of one of my other tridanca clams detached and lying in the sand next to it. I also noticed a layer of slime-like algae on the shell, and I don't have any slime algae anywhere else in the tank. The clam still reacts to changes in light intensity, but I think it's on it's way out too. Is there any hope for it once the byssal gland is removed?

The only recent change in the tank is the addition of several corals and some live rock from a friends reef aquarium who decided to quit the hobby - this was a couple weeks ago. I have not been able to spot any parasitic snails on any of the clams, but I think something from his tank must be causing this. Does anyone have any ideas what it could be? All of my water parameters are normal and stable, and all corals and fish are thriving.

I attached a picture of my Deresa. It didn't look normal today, so I picket it up to look at the underside and it wasnt attached to the substrate any more.. The byssal gland is damaged, and it looks like it's about to fall off... If you look closely there are bristle worms, and a trilobyte/rolly polly looking thing... I've always had the bristle worms in my sand, and I don't think they are causing the problem. Does anyone know what the other thing is? Should I remove it from the tank?

Any help would be appreciated.

 

[Anonymous]

It sounds to me like you introduced some kind of predator with that LR. Unfortunately I don't have a guess as to what it might be. I can tell you for certain that the "trilobite" is definitely not doing the damage. I'm pretty sure that's a chiton, or polyplacophoran, a harmless algae grazing mollusk. Maybe try putting your clams in a critter keeper or other secure container that allows light and a litlle flow in, but keeps whatever doing it out. Good luck.

 

[Minh Nguyen]

The byssus thread in your Derasa is normal. Once the Derassa get to certain size, it lost it's byssus glands. The Chiton is harmless and not the cause of your clam's death.
Did your friend have clams that died before he breakdown his tank? How large was your Maxima and did it grow verymuch over the last year or so? How much light you have hime under? Any change over the last year? Did the Maxima have any hole bored into the shell?
Minh

 

[Osama]

I found out in my case that after I moved ny clams off the sand bed onto rock that they were not bothered by little snails or any other animals. I lost one clam in three years. Try cleaning the shell of anything that looks as a potential irritant. Dip in fresh RO water that is at same temperature as the tank for a minute or so Shake the clam in the water to loosen anything off its body & put it back at a higher elevation on the rock. this worked for me Hope it works for you. See my tank: http://www.theculturedreef.com/featured.htm

 

[Anonymous]

???

I've never heard of exposing clam tissue to RO water as being a good thing. External parasites can be removed with a good daily scrubbing of the entire shell with a toothbrush. I suspect that a pyramidellid snail egg could survive a one minute freshwater bath anyway.