Hi I have a baby pima, about 7". He has recently lost his appetite and seems to have something irritating his gills. He will stretch his mouth and often will pop his mouth-like he is trying to eat something- in the open water. I have treated the tank with prazi-pro about three days ago and just yesterday did a 50% water change and he is still doing it and swimming around very lazy like. What do you think he has and what should I do? Thank you.