I have dwarf puffers, and I've done a lot of research on them before I started keeping them. They do LOVE snails (pond snails and ramshorns) -- not Mylasian Trumpet snails, though, as their shells are too hard.
Dwarfs don't seem to suffer from overgrown beaks, thank goodness. Mine don't really crunch on shells anyway, they prefer to just nibble on the snails.
I feed mine live blackworms (which they devour). Frozen bloodworms are supposed to be a good staple for them, but mine won't eat them. I think mine want only live foods. So, mine eat live blackworms and pond snails and ramshorns. I'm looking for other live foods to feed them. I have ghost shrimp in there, but my DPs have not discovered that those shrimp could be on the dinner menu (yet).
DPs need about 3 gallons each. You can keep 3 in a 10 gallon. Ottos are one of the few recommended tankmates. It's best to keep one male with multiple females (although sometimes females can actually be more aggressive than males). It often comes down to the personalities and temperaments of individual species.
Their tanks should be heavily planted/landscaped with plants (live or fake), rocks, caves, flower pots, etc... to break up their line of sight in the tank and to create natural territories. They can be very territorial, but then again they can also decide to school together. It can vary from day to day, depending on which sides of the bed they get up on that day.
They are funny little creatures. I enjoy them a lot.
