When your fish hurts it's self while you are cleaning the tank. While my hands were in the tank doing a water change today my jar darted to the caves and ripped up the side of his/her face a little and tore up a scale on his/her back
i know what you mean bro the first time i got my JAR evertime that i clean his/her tank he/she freakout and loose a scale or two and im cleaning the tank twice a week.... just monitor the wound do a WC add some salt and up the temp up to 86 degrees...