Crunchy food for puffers

[CowMoo]

What would be a good food for to wear down a puffers teeth? I don't have space to set up a culture for snails so i filled up a mason jar with water and stuck 3 pest snails in. I plan on feeding them flake food. Would this work?

 

[CowMoo]

Nvm i made space for a little tank.