I have a blue betta fish named Zuko and we have owned him for about a year. We have been keeping him in a ten gallon filtered, 78 degree heated tank. He has been a very active and healthy fish until about a month ago, when he had been laying at the bottom of his tank. He couldn't swim to the top, not even to eat. He had early signs of fin rot and pop eye. We put him into a smaller container so that we could treat him, and we bought an air bubbler for his tank as well and in no time he was back to normal. (about two or three days.) we changed the water in his ten gallon tank and slowly got him back into it. Everything was fine for about a week. Then he was stuck floating at the top with a bulge on his side and wasn't eating.. We did research and thought that he was constipated so we fed him a piece of a pea and a few daphnia and he took a huge poo and the bulge slowly went completely away, but he continued to float at the top. we had read that it may take some time for him to regain buoyancy, so we gave him a few days and now I really think he may be dying. The bulge on his side is really HUGE now and super pronounced. He was floating practically out of the water and buckled basically in half. he was eating for a little bit and then stopped completely. He is getting so pale and now he gets sucked up into the filter. we put a little net thing up so he could stay in one place, but i think it made him worse because once we took him out of it he sank to the bottom and is currently still at the bottom face first. we have checked the ph levels and they are fine. we have tried aquarium salt, specifically to treat him we had used pimafix and melafix first and after that maracyn two. We don't know what to do and we really love him and dont want him to die. please if anyone has any ideas im willing to try anything that could save him so he doesnt have to suffer anymore. thanks for reading and if you respond thanks for your input.
^^these are four pictures i took three days ago when we knew he was just getting worse of the ridiculously huge bulge and he was so pale. please help.