Even the tiniest and most docile of fish can become aggressive monsters of your reef. Clownfish, tangs, and even Chromis can all become territorial to virtually every other fish in the tank, causing fin nipping and other harmful interactions between your aquarium’s inhabitants. These fish can even draw blood when attacking the hand of an intruding aquarium hobbyist. When these fish become extremely aggressive, the only solution is to remove them. Grab a fish trap, load up on patience, and hope you’ll catch the terror without having to tear your aquarium down to do so. Once caught, put the fish into solitary confinement and maybe if it calms down, you can put it back into the tank. Of course, you might have to do it all again if the fish’s temperament doesn’t change.