Clam getting enough light?

[jsc4354]

Well, I purchased a derasa clam over the weekend because I read they are the best to start off with. Now, when I got it home I noticed it will expand and contract on its own as it should. My question is how much can the mantle protrude from the shell? The reason I ask is because I read if the mantle protrudes too much it is not getting enough light.

I currently have VHO lighting (6 x 110watts) on a 120 gallon which equates to a little less than 6 watts per gallon. Also, I placed the clam higher up in the tank and it fell. So, I placed it on the bottom.

Thanks,
John C.

 

[jsc4354]

I just read another thread and found the correct term for what I was asking is hyperextension. How much extension is considered too much?

John C.

 

[Peabody]

That's fine. No hyper-extension.

IME, Derasa (as well as gigas, which I have never kept) require the lowest light. WAY less than maximas or croceas. You should be fine. (They also prefer the sandbed instead of the rocks)

 

[mbbuna]

i think you have plenty of light for a Derasa. looks good