My Mala is breathing hard.

[BTruss]

I have had him for 6 years in a 125 with no issues. But recently he has started to breath really heavy and for a bit he had issues with swallowing his food and keeping it down. I have checked the water prams and nothing jumps out. I have a powerhead and some air bubbles in the tank. Im not sure what the issue is. He still wants to eat but i have noticed he is not quite himself. I recently treated him with melafix because he has some hith. and that has helped. would that have something to do with his laboured breathing? Im not sure what to do at this point. Any insight on this would be super helpful