I lost three six inch tinfoil barb and a two inch pictus due to the pictus swimming up the filter and clogging it then the I saw the fish gasping for air. since the filter runs very quietly and it was after a water change. when I found out what happened it was too late and It seemed like the tinfoils were long dead. put luckily for my pleco and synodontis and remaining pictus made it. but not all losses are bad. Like when the Chinese Algae Eater pesters everybody and he ends up dying.
