Wierd hippopus shell growth

[kbecker]

I was browsing the clams at the LFS when I noticed some H. hippopus with what looked like it had a double shell. What I mean by that was it looks it had died but ressurected itself and grew another shell inside of the old one.

What would cause that? More importantly is the clam healthy? The clam reacts to shadows / movement above it and does not appear to be gaping.

I am interested in getting one, but all searches on the internet for pics of H. hippopus shows a normal single shell and not this double shell. There are two clams in their tank like this, so I dont know what to make of it.

Thanks for any help / comments.

 

[acroporas]

Yes, this is common in all the different species of clams. It happens when the clam stops growing for an extended period of time and then later resumes growth.

So long as there is a nice white border around the edge of the shell (this shows recent growth) then the clam should be fine. It is probably a sign that the store you that has it now is taking much better care of it than it's previous owner(wholesaler).

 

[Vili_Shark]

I dont think that's what Kbecker meant.

The farm in Marshall islands had some problems with their hippopus, their clams looks like "double" shell.

it's not like the regular growth that a clam usualy shows.

This was due a problem believed to be poor water quality that caused this.
However, the clams are in good health now, just have kinda double shell.

 

[mad mechanic reefer]

You mean like this -

 

[kbecker]

Well yes, but a bit more pronounced. The outer shell layer is about the same height or slightly lower then the inner shell layer and about a 1/4" gap (but filled in) between the 2 shells. More like this crude ascii cross section: ((_))

 

[acroporas]

Yes that is caused as I said before from when the clam stops growing for an exteded period of time. The longer it wasnt growing the more pronounced the shell marking will be. Sounds like your clam had stopped growing for a very long time.

As long as the clam shows signs of recent growth all should be good.

 

[kbecker]

Thank you all very much. All of your comments have reassurred me that the clam is healthy so I will go pick one up this weekend.