If you're looking to breed your own food, you can also look into Ghost Shrimp or Red Cherry Shrimp (or some other small shrimp, like Bee shrimp). You just set up a little 10 gallon, put in a piece of driftwood, and put a bunch of Java moss around it. Once in a while I throw in a very small piece of frozen broccoli to get some algaes/organisms to grow, which the shrimp will eat. The live shrimp make tasty and exciting snacks for the puffers, as they actually have to chase them! Some people will even set up a 10 gallon with about 4-6 Apple snails and 4-6 Ghost Shrimp. The shrimp will eat some of the baby snail eggs, but since the Apple snails lay so many, it won't hurt the population very much.
Just make sure you stay away from the Malaysian Trumpet Snails (like Jase said). They're the ones that look like spiral cones. It's not that the puffers can't eat them, but they have the potential to chip teeth (since they're so hard). I've fed my Ceylons MTSs before, but I always crush them between my fingers before feeding them so that the shell isn't as hard.
Hope that helps!
