Pacu with ? tail/fin rot/ich
I have a pacu in a 90 gallon tank. He was doing well until I made about a 50% water change (had missed a cleaning) with a gravel siphon. The fish had no signs of anything being wrong, no white or ulcers anywhere. The next day he had developed a white film over his eyes, then noticed white on his tail and fins that became ragged looking. I treated him with Melafix as directed 7 days. He had just a small film on part of his eye. I then did 25% water change and treated him again. After this water change, he developed the film on the eyes and back on his fins, a what looked like a small sore on his mouth. I treated with Melafix again, did not completely go away. I treated with Parasite clear 3 days (from Walmart), not getting better, then treated with Fungus clear 3 days (from Walmart) and not getting better. So, I went back to the Melafix, got a little better, but not completely. I afraid to do another water change thinking it may get worse. During all the med treatment, the carbon filters were out. Twice during the treatment, he has developed a redness under his mouth and currently has a redness on top of his mouth, just splotchy looking. I would appreciate any input on what I should do next.