Mine love snails and shrimp of course, but they also eat frozen blood worms. I take a glass of aquarium water and drop the frozen worms in it. When they have all thawed, I dump in tank. Only bad part is all the other fish seem to like them too. Since my Ceylon puffer is big enough, he gets crayfish too. The gsp gets some after the kill, LOL. He will go in and steal some, but it seems the Ceylon doesn't care. The hang around one another a lot. Crabs are good too, and with smaller puffers, they can usually get them buy themselves. The crayfish and crabs wear their teeth down. I also feed frozen half clams, using the same method as the frozen blood worms.