fresh water clams/oysters

[WestTex]

I have kept FW Clams in my 55 gallon for about 8 months now. They lay partially buried in the gravel and filter the water. I have done nothing other than feed my fish their regular regimen (flakes, shrimp pellets, and cichlid pellets) and the clams seem to be doing fine. As for water flow I have a Marineland H.O.T. Magnum Canister and a powerhead circulating the water.