derasa has retracted mantle on only one section

[MikeG]

My three week old derasa has been doing fine since adding to my. I returned from work today to see a nice chunk either missing or retracted from my derasa's mantle. I would estimate that this totals less than 1/6 of the total surface area. The only fish I have are a PBT and two firefish.

I did throughly clean/inspect the shell before placing it in tank. Water parameters are:
NH3 = 0
NO2 = 0
NO3 = 0
Ph = 8.2
Ca2+ = 420
Alk = 3
sal = 1.025
temp = 82--84F

Any ideas?

Mike

 

[jim norris]

MikeG,
What type of lighting was he under and what type is he now under in your tank? Also how big is the clam?
Jim

 

[MikeG]

Jim: He was under PC at the LFS, and now he has been under 2x150 MH, as in my sig. The problem doesn't seem to be with expansion -- the remainding mantle is "picture perfect." He is just either missing or retracted one ridge right next to the inhale siphon. It really looks like someone took a bite out of him. Sorry, no pic. He is 2.5"

Thanks for your help
Mike

 

[jim norris]

Mike,
Any creatures like shrimp or crabs in the tank?
Jim

 

[MikeG]

Jim: I do have "clicking" in my tank but I have a thread going on the mantis forum and I was told it was not likely. I removed a beige hairy crab before the clam arrived -- maybe there is another. Many of my acros have small crabs with them.

I do not have any oramental crabs/shrimp.


thanks again,
Mike

 

[holeinone1972]

Crabs and clams are not a good mix. The ones that live in your acros, should be o.k.. But that clicking is probably a pistol shrimp. I have not heard of problems with those, but that large hairy brown one bad lil buggers they are. It is of course possible that your lighting is shocking your lil clam though. Did you acclimate it to your lighting?

It is a big difference form the lfs's and yours, you must be carefull, or you will give your lil buddy a sunburn. Best of luck, and watchout for those hairy crabs. Rob

 

[jim norris]

Mike,
Holeinone1972 is right about the acro crabs. There is a nasty picture of a sharon shrimp eating a clam in one of J. Charles Delbeek and Julian Sprung books. I do not trust shrimp other than a blood fire shrimp.
Jim

 

[MikeG]

holeinone1972: Yeah, I think there must be some sort of shrimp in there, but I have never seen it. Do you know any way to trap him? commerical or home-made? Anything please!!!! I got the little guy I am totally hooked! I am just waiting for this mysterious viral illness to pass and I'm up for more! But first things first, to make my tank clam safe.

Jim: I saw that pic in Delbeek and Sprung's book. I hope I dont' have that.

Also, I do not think I rushed his acclimation. He is flawless except for this lesion, expanding wonderfully, but I guess anything is possible. He is showing a little more of his wound. I might be a MD but I'm new at diagnoising infections in clams; I hope he will heal without any problems. Do you know if they scar?

Mike

 

[simonh]

Another thing to watch out for is sweeper tentacles at night on large polyped stony corals. I have seen these cause irritation sometimes to clams resulting in part of the mantle curled inwards. However, if tissue is dissappearing then I would agree to lookout for fish nipping or shrimps and crabs on a night with a flash light.