I have 3 pea puffers/ dwarf puffers, that I feed frozen bloodworms 2 times a week, pond snails every other day, and dainichi cichlid baby sinking pellets every day! They need a lot of food, it doesn't have to be live, you can also feed brine shrimp, and any other pest snails, they don't actually need snails because they don't have a quick growing beak like many other puffers, and snails would be used to cut down on the beak or tooth! Weekly large water changes will be great, and they need hiding places in plants and decorations if you plan on keeping more than 1. I have my tank full of live plants!
From experience, they really aren't as aggressive to each other as everyone says, just aggressive to other fish!
If you have any questions I would be happy to answer them!