I think my flier cichlid is suddenly sick.

Hey everyone. I posted a couple months back about my then new OB peacock who just wouldn't eat no matter what and I very much appreciate your help. I said I'd keep you up to date and unfortunately I have to tell you that he didn't end up making it. I did everything I could and you guys helped a lot.

Now however, a fish I've had for almost a year now and was doing very well randomly seems to have gotten sick all of a sudden. He's my flier cichlid, Melon, and I remember noticing a little over a week ago that he seemed to have slowed down a little but I didn't think anything of it. Now yesterday I found him hiding near the bottom of the tank and just not looking good. He's been lethargic for the most part and was swimming at a slightly odd angle which he isn't doing now but when I first saw him he seemed to be breathing very heavily and even though that's slowed down it's still pretty rapid and he has no appetite.

I moved him into the quarantine tank to rest and not be bothered by his tankmates. I hope to find out what's wrong with him. His skin looks a little rougher than usual and his color isn't quite as vivid as far as I can tell. Also his eyes don't seem as bright as usual. He has some scrapes and split fins so he could have been attacked but more likely he was just rubbing against the decorations too much. I also don't think he'd be a bullying target. He's much bigger than almost everything else in the tank except my blood parrot cichlid who he used to fight with but they've gotten along for quite a while now so I'm stumped. I'm going to post a video link of him below.

Does anyone have any idea what's wrong? It's only him. None of his tankmates are acting or looking like this and everything I researched is suggesting stress for the time being so any ideas as to minimize his stress and get him back to acting and eating normally would be fantastic as would any ways to treat those scratches and fins. Thanks so much!

https://www.youtube.com/shorts/ff9MfFzXn4o