Saw a couple threads on dwarf puffers tonight. Although i am not an expert on
fw puffers, I gave managed to keep 4 out 4 alive and well in a heavily planted, well established 20l for about a year now. I also keep Amazon puffers, few months and 3/3 are well. Few things to consider.
Health- while you may be told they're tank raised, id be willing to bet they're wild caught. You should always treat
wc for parasites, especially dp, ifvtheyre not eating and seem lethargic act fast.
Environment- each puff should have 5
gal, if you add more than structure for defining territories is a must as they're potentially aggressive and territorial. They're not community fish.
Food- I feed mine frozen blood worms, brine shrimp and glass worms. Live snails are added to the tank monthly. They eat the shizz out of blood worms. If you're do not than they're probably sick or stressed.