I recently got a clownfish on Sunday. He’s in a 20 gallon quarantine tank with copper(cupramine). And I have not seen him eat and he has stringy poop. He also goes to the top of the tank and sometimes swims vertically with his but up. Is this an internal parasite? He doesn’t look bad. Or is it swim bladder? What should I do there are 3 other fish in the quarantine tank?