They will get about 24 inches or so, and really need a 250+ tank in my opinion. They love inverts including corals, and once they get big enough they will crush the snail shells and eat the snail. They eat a general meaty died, crab, mollusks, fish, shrimp, some greens, they need hard stuff in their diet because their teeth never stop growing. Most care you see for a dog face will translate over well for the larger puffer.