I own a dog face puffer. Most things that people claim they will eat, mine won't. I put some glass shrimp in there for a snack for him (the shrimp are surviving because I am in hyposalinity) and he won't eat them.
When I did add fish to his tank he felt invaded in his own house and hid for a while.
He is a mush-cake and I don't think he would bite a flea.
I have heard that you shouldn't keep puffers together though.
When he was held for us at the lfs, there was a tank next to his that had a stars and stripes puffer in it. When I went to visit our little guy while our tank was in development, I would bring him food and visit. One time, I gave the puffer next to him a little peice of food too, and my little guy was jealous.
Puffers are
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cats. At least mine is.