I bought a trimac about a month ago at about 2.5" and he was in perfect health ate like a machine. The last week he hasnt touched a bite of food just sits on the bottom of the tank doing nothing. His colour is faded out and hes starting to waste away hes not breathing heavily and theres no white feces I can see just has zero interest in food any ideas? water paramaters are ph 7.2 amonia 0ppm nitrite 0ppm nitrate 5ppm temp is at 82