It's common for them to have internal parasites. Since he is in the display I don't know if you would want to treat for that just incase. Also get krill with the shell and grocery shrimp with shell for his beak. Hermits and emerald crabs are good as well just break the emeralds pinchers off . I'll be honest I am worried about the size of the fish you have with him . I think he may not get as big as he can when all your fish get to adult size. I'll hook you up with more info after work.
Feed your Filtration
Give it to Porc Chop he'll eat anything!!!!!
"This is my tank and these other fish just live in it"
^ Quoted from Porc Chop^