The following ,all from the local grocery store,,raw frozen shrimp, scallopes,tilapia fillet,smelt,squid, trout.
Occassional Nightcrawlers from untreated lawn and kens sinking pellets 9.5 mm size. The pellets do increase the waste output from the fish though,which is why I only feed a few at a time kind of like a vitamin. Good luck with yours , they are great pets.