"Dwarf Puffers, Things I need to know?"
That they are so cute!

LoL I remember doing all sorts of research on them almost a year ago but I can't find them around here. I can't remember most of the info, but I hope this helps you a little!
5 gallon minimum for one Dwarf Puffer (somebody else may recommend otherwise, but most sites I found about them said 5 minimum).
They are freshwater fishies. I'm not sure if they will do well in Brakish or not.
I know they eat Brine Shrimp and Bloodworms, and I read they should be fed small snails now and then to keep their teeth down.
They are aggressive and I read that a larger tank is needed to keep more than one. I heard that a 10 gallon might be able to hold 2, but I'd check with somebody else on that. Don't keep them with fish that have long fins.
This Link has some more info about them. I forget where I put my other links about the puffers though. I can't seem to find them -_-
I haven't personally owned them, these are just bits of info I remember reading when I was researching them in the past. I thought somebody else on here had some but I forget who. I'm sure others will offer further advice about them. Good luck if you get some! They are such cute little guys and I really wish I could find some around here for sale -_-