Chocolates are scavengers and will eat stuff on bottom of tank and glass. They do need meaty foods tho. I used to feed my chocolate krill and anything from seafood depo at store. I'd threw it in some tank water and garlic. The hold it between the chocolates stomach and glass. They'll take care of it from there. If you're looking for a cuc, I'd get some turbo snails and a handful of crabs. Not sure if a conch will fit in your tank, but they're my favorite when it comes to cuc. Goodluck! Oh and Mr_X knows his stuff... So ditto on what he says.