Valintini's are notorious fin-nippers. They need around a 35-40g tank. They will eat brine, silversides, squid, mysis, clam, shrimp, maybe some flake, and formulas 1 and 2. As for the beak, they will bite the live rock occasionally to file the beak down. Leaving the food still a little frozen might help as well. Valentini's are very hardy fish and a great addition to most aquariums. Bo