My problem was when I got my 55 gallon years ago. I only got my fish from pet smart and said this was okay everyt ime I asked them. My stock was a dwarf blue gourami, 1 rainbow shark, 1 albino cory cat, 2 clown plecos, 1 rubber lip pleco, 1 twig catfish, 1 eclipse catfish, 1 angelfish, 1 synodontis eupterus, and 1 peacock eel. The gourami, rainbow shark, 2 clown plecos, and cory cat were from my first ever tank. Suprisingly the gourami, cory cat, and peacock eel survived this and lived for a long time. The gourami died in a cleaning accident about 2 years ago, cory cat died 6 months ago and the peacock I sold just a couple months ago since I got tired of only seeing him once every few weeks. This act of fish murder still haunts me to this day though.