I bought an established tank off someone that was a 55 gallon with 2 emperor 400s on it and a power head powering the UV and had a decent amount of fish in the tank and worked great for years. The guy had a trigger, yellow tang, purple tang, lion fish, hawkfish, foxface 2 clowns, few damsels, lawnmower blenny and a few others i forgot. Yes i believe it was overstocked but everything got along great.