I kept one with mine and they did great-actually the niger was the meanest bas*$rd I 've got--I mean he is a mean SOB--the lion died from an apparent blow from my foxface-(the lion jumped up to get food, and landed on the fins of the foxface)-again, I would just be careful and not overload your 75, because with these fish, you can't have a clean up crew-they will eat them-so keep in mind you're gonna have a kinda nasty tank if you don't do pretty frequent water changes and have good filtration-and they will "butt heads" more also in a smaller tank--and if you do get a lion-PLEASE don't feed him feeder guppies or comet goldfish-it is a slow method of starving them-they can't digest their bones-get them to eating prepared foods-mine ate right out of my hand-literally