Here are the answers to the questions:
1. I have a 1 gal. triangular-shaped tank bought at Petco that comes with an air stone and tube, light andno actual filter.
2. I use tap water that I dechlorinate with Wardley Watercare Chlor Out
and also a few drops of Stress Coat.
3. This has been the setup ever since we've had this fish, 2 years. I have natural aquarium rocks, approx. bean sized.
4. He is a single occupant, he ate 2 ghost shrimp and a cloud fish 2 years ago.
5. He has a plastic plant, the real one turned to mush. The plastic one has been in the tank for a year.
6. The temperature is room temp. When I change it I make sure, by touch, that it's not too warm and not too cold.
7. No filter, just the air stone that came with the tank.
8. What is a CO2 unit? I guess since I don't know the answer would be no.
9. It receives natural sunlight light all day long, indirectly. It's not sitting directly in the sun.
10. The last water change was done a 1 1/2 weeks ago.
11. I change the water approx. once a month. The tank doesn't really get dirty. I noticed that the plant leaves have gunk on them after just cleaning them, which is odd, so I know somethings up.
12. I feed my fish once a day in the evening, either Betta Bits or Blood worms, the blood worms not that often. This has been the only food I've ever used for my fish.
13. The lighting is the light the came with the tank and I don't really keep it on because he starts to get all aggressive because he sees his reflection and starts to attack the glass.
14. My concern is the bulge on his side. Lengthwise it goes from his side fin to almost his top fin and widthwise it goes from the bottom of him to just over his mid section, so just more than half his width. It developed a few weeks ago, out of nowhere. When I turned on the light right now and he was at the top I can see the light in it, like it's an air bubble so it's not a solid growth. It doesn't prevent him from going to the bottom and staying down there. But his demeanor is a bit stressed.
15. I don't test my water parameters, am I supposed to with this type of setup?
17. He's 2 years old and like all the other bettas he kind of just sat there due to the cramped confines of his cup but he did move around when we picked his cup up to get a good look at him.
Please help! I'm afraid if this bulge gets any bigger it's going to pop and that wouldn't be good.