Well I was down to 10 primary fish in my 220. I had 7 Bucktooth Tetra (Exodon) and 3 Striped Leporinus. They where getting along rally well but I wanted to turn that tank in to a salt water tank. A coworker gave me a 55 gal tank. so I put them in it. I put a power head in the tank to make a lot of flow in the tank.