Omega-3 Improves Your Pet Health

I bought a Shubunkin fish back in early February with a bowl (for my dorm room). By the end of the month, my parents bought me a 5 gallon tank for him (I know that it’s a he). I bought another Shubunkin not too long after I got the tank, but she died a couple of weeks ago, I’m pretty sure she was sick when I bought her though, from what I suspected was swim bladder. Which, to my understanding, isn’t contagious.
Since then I did 1 major water change (60%ish) and a few small ones. I admit, I’m not the best water quality maintainer but I try to change the water when I can. I know I don’t over feed him, because I feed him once every other day. I used to feed him more often, but I would never see him eat and I would see all the food on the bottom of the tank (which made the water dirtier).
So I was looking at him tonight because I noticed that he’s floating at the top of the tank, like the other one was doing about a week before it died. Just within the last day his body has become bloated and his scales are protruding. He kind of looks like a pine cone. The other fish did look a little bloated, but not pine cone-like. The last few days have been really hot in my room where the tank is, and I know he’s a cold water and his water is never really that cold would that be a big problem?
I figure it’s either swim bladder, bloat or constipation. I only feed him flake food because I’m not really sure how to prepare any other food for him.
I’m really concerned for his health because I’ve had him for 5 months and I would like to keep him a while longer. He’s survived two moves from university to home and potential cat attacks, I would hate for constipation to be the thing that gets him.
Any response would be appreciated, the faster the better because I really want to get him healthy again.

I bought a Shubunkin fish back in early February with a bowl (for my dorm room). By the end of the month, my parents bought me a 5 gallon tank for him (I know that it’s a he). I bought another Shubunkin not too long after I got the tank, but she died a couple of weeks ago, I’m pretty sure she was sick when I bought her though, from what I suspected was swim bladder. Which, to my understanding, isn’t contagious.
Since then I did 1 major water change (60%ish) and a few small ones. I admit, I’m not the best water quality maintainer but I try to change the water when I can. I know I don’t over feed him, because I feed him once every other day. I used to feed him more often, but I would never see him eat and I would see all the food on the bottom of the tank (which made the water dirtier).
So I was looking at him tonight because I noticed that he’s floating at the top of the tank, like the other one was doing about a week before it died. Just within the last day his body has become bloated and his scales are protruding. He kind of looks like a pine cone. The other fish did look a little bloated, but not pine cone-like. The last few days have been really hot in my room where the tank is, and I know he’s a cold water and his water is never really that cold would that be a big problem?
I figure it’s either swim bladder, bloat or constipation. I only feed him flake food because I’m not really sure how to prepare any other food for him.
I’m really concerned for his health because I’ve had him for 5 months and I would like to keep him a while longer. He’s survived two moves from university to home and potential cat attacks, I would hate for constipation to be the thing that gets him.
Any response would be appreciated, the faster the better because I really want to get him healthy again.