You said this is a dwarf puffer? They don't have nearly the teeth problems that other species have, but its still good to let them chew on hard shelled things ocassionally
If you haven't found it yet, check out the Dentistry article in the Library, there are pictures of puffers with overgrown teeth.
My dwarves were very picky eaters, they would only accept live bloodworms, a certain pelleted food and the rest of the time they hunted their own food. I had them in a 33xl tank that was very overgrown in plants and had a very established population of red cherry shrimp and a variety of snail species.
Of course, if you are starting from scratch, it will be hard to get anything like that established. But you can give them the ocassional ghost or red cherry shrimp as a snack to hunt down, and once you find some snails they are easy to breed so you always have a supply. The red cherry shrimp are a bit more expensive because they are pretty, but they breed like rabbits in freshwater and are a perfect size for dwarf puffers to hunt down
