I have a 22 gal Nano cube reef tank. It is running about 6 weeks and all water tests are OK. I just bought a Foxface and was told to put a piece of lettuce in the tank for it to feed on. The guy at the fish store also said it was safe to put a Zenia in the tank. Will the fish eat any store bought fish food? After doing some research I am afraid it will eat the Zenia. Any suggestions?