My betta fish has been sick for about a week and a half now. He seems very bottom-heavy and lays on his side a lot. His gills are also VERY red and inflamed but it can't be ammonia or nitrate poisoning because I took a sample of his water into the pet store and they tested it for me and it came back fine. He comes up to the surface for food and air but it seems very hard for him to swim up. His head and upper portion of his body are bigger than normal too and it seems like it's hard for him to breath. I've also never seen him poop?? His tank is 1 gallon, he has a filter and a heater, I do a 25% water change every 3-4 days and I clean his tank every 1 1/2-2 weeks. I feed him 3 Aqueon color enhancing pellets in the morning and 1-2 bloodworms at night. For the past few days I've given him a quarter of a pea at night but that doesn't seem to help. I tried giving him a MARINELAND all-in-one remedy that treats parasitic problems and infections for 5 days but he hadn't improved either. Please, please help if you can! I love my betta so much and I just want him to feel better!