Hello, I’m not sure what to do, I have two tanks one is perfectly fine and has been running for 4 years and we even have sharks, and this one has been running for 2, we recently added a file fish along with a valitini puffer, everything was fine untill about 3 days ago, I found the old valitini dying on the ground we scooped him up and put him in a different tank he died within the next hour, he had cloudy eyes before he died then two of my clowns died within a hour, then my powdered blue tang started rapidly breathing along with the damsel fish we moved them to another tank with water from my shark one, the rapid breathing hasn’t gone down and the parameters and oxygen are perfectly fine, I don’t know what to do, if anyone could give an idea, that would be nice!