I currently have one 7" Sun Catfish housed with a 7" Black Bullhead in a 75 gallon tank. I would like to know if I could put my 2 Synodontis Epterus with these 2 other catfish? The bullhead and sun cat seem pretty mellow but I don't want my Syno's becomming lunch. The Syno's are about 3.5" long ...