I have a green spotted puffer in a 29 gal with several cichlids and they mainly stay away from each other. I've heard that animals that are toxic in the wild have the appropriate signs to let other animals know, "don't mess with me". The only problem I have is that the cichlids don't let the poor puffer finish a meal. I feed him freeze dried krill cuz that's all he will eat and as soon as the cichlids are done with the flakes they will snatch his food away. I will admit tho, a few months ago I lost a Haplochromis Obliquidens because he kept attacking my giant figure eight puffer I had and he did kill it eventually which pissed me off but not only that he died the next day. I've had a puffer in all my cichlid tanks (3) for over a year now and that was the only problem I had. I guess what I'm trying to say is try it out.