Please Help Identify Hitchhikers

[KYyada]

I need to know what this is. It is on some live rock I bought. Is it something to keep?

 

[KYyada]

Sorry I realized I was using thumbnail URL's

Sorry I realized I was using thumbnail URL's

 

[LeslieH]

They're bivalves, maybe ark shells. Harmless filter feeders.

 

[KYyada]

kewl, Thanks for the reply. I wonder how much they eat? I only have a 20 gallon tank but no predators. I have two....

 

[LeslieH]

Filter feeders feed most of the time. In nature they eat far more than is available in the typical tank. Your tank probably doesn't produce enough particulates to keep them happy so supplemental feeding might be good. Try posting over in the "Clams & other Mollusks" forum for advice on a good source of nutrition for them.