there are many different puffers sold as 'red eye puffer'. I've seen Tetraodon palembangensis, T. lorteti, T. irrubesco, T. cutcutia, T. cochinensis (sp?), and T. leiurus all sold as 'red eye puffer'. most of these will stay smaller in the 3-4" range though the palembangensis (probably not the red eye puffer in question though) grows to around 8" I think. pretty much any of these would need to be in a species only tank.
if its carinotetraodon irrubesco they get to about 2", 75 82 F, can be kept in pairs i think, and maybe with other short finned fast swimming fish, but thats a trial and error about neutral pH. eats live and frozen foods-bloodworm etc. males have a red tail, females dont.