I did a water change and tested water parameters which seems to be normal. I even added at least 1 ml prime each time I added water. And I probably added 5 capfuls by now. But the fish has been gasping for air all day and looks pink. I can’t figure out what’s wrong. The pH is 7.4. Ammonia is 0. Nitrate is 0. Nitrite is 0. Should I wait it out?