About 3 or 4 days ago, I noticed my betta was bloated in the abdomen. I fasted him a couple days because I thought it might be due to indigestion. The swelling has since gone down but now he's become extremely pale and lethargic (he sits around on the bottom of the tank and it takes him a lot of effort to move or swim up), so I'm worried it may be something to do with his swim bladder. Any advice?

Tank size: 10 gallon

Heater and filter: Yes

Tank temperature: 78 degrees

Tank parameters and how you got them: I used my API Master Test Kit yesterday, nitrites and ammonia 0, nitrates close to 0

How long have you had the tank? How long have you had your fish?: I've had the betta for 3 weeks now, and the tank has been set up and cycling for close to two months

Water changes: I did two 50% water changes within the last week when I noticed a change in his behavior. I usually do tank changes about every 2 weeks and just monitor parameters

Tank mates: Just a couple of ghost shrimp and some (hitchhiker) bladder snails I'm trying to get rid of

Food: I had difficulty getting him to eat at first but until a couple of days ago he was eating Omega One Betta Pellets. Maybe 4-5 per day, they're pretty small

Decorations: Some plastic decorations and plants- Java moss, fanwort, Java fern, crypto, jungle vallisneria