im upgrading to a 180 gallon for my big guys and i got my 75 gallon with a O. Bichir, striped rafael cat, and a needle nose gar. i want to add one more tankmate and i was thinking a large puffer because of how mean they are when they eat. is a fahaka puffer get too big for a 75 gallon? and what other puffers might be good for a tank this size? i know some puffers require brackish and dont want to go brackish since my other fish get iffy with salt.