How should I treat or QT cat shark? One of my sharks is having some erratic swimming and flashing/scraping the sand.scraping her side/gill areas and sometimes doing a spin. She is eating and still active. I used dechlorinated tap water for water changes the last two times and then she started having the symptoms so I am not sure if it has something to do with it (maybe stress from hard water/heavy metals)or just coincidence that symptoms started. I know they are sensitive to things and I am trying to make sure I fix whatever is going on before she is too stressed. She chases down food still. Hoping to get someone's expert opinion on this. Thanks