Mbu puffer is 26" check my gallery for picture,and when he fans his tail it is over a foot deep.Having said that he is a social mbu,some are killing machines some are happy with company.His best mate is a channa marulioides and hes also in with a longibarbis 24" and two giraffe cats one 20" one 24".One from the same batch as him belonged to someone we know and it killed an 18" gibiceps imediately it was put in his tank.Benzjamin13,post which puffer your wanting and we will give specific advice.One misconception is that all puffers need some salt,many are freshwater only.