goldfish swim bladder issues with unknown cause? PLEASE HELP
iím new here, but iíve been raising goldfish for eight years now. recently, my last remaining fish has gotten sick. i usually know what to do, but iíve tried everything and he isnít getting better. i was hoping someone else would know what to do.
20 gallon tank, one fish (6inch comet goldfish, eight years old). have a bubbler and a filter system. regularly change the water every week or two. have been feeding him flakes his whole life (which i know i shouldnít do). nitrites/nitrates/ammonia levels are all normal. have treated with API stress zyme bacteria, stress coat, ammo-lock, and melafix. introduced a new goldfish that i rescued from an overcrowded school science tank a few months ago, but that fish died very suddenly a few weeks in. worried that one may have brought in something?
did a 50% water change as soon as i noticed him acting weird. got back from a five day vacation to find him darting around the tank and having some mild swim bladder issues. fasted him for three days, then tried to feed him mushed peas. he wouldnít eat them. his condition got worse and he ended up on his side at the bottom of the tank having issues swimming. started treating him with melafix doses every day. he seemed to get better a few days ago, he was back up and swimming around like nothing had happened. that didnít last, and heís been stuck at the surface of the tank now for two days. he canít swim down at all and is often just floating on his side. has refused every type of food iíve offered (flakes, pellets, and peas). spits out anything thatís hand fed too. as far as i know, he hasnít eaten in over a week now (unless he had a pea or two that i left in there, i didnít count how many went in at the beginning).
i really donít know whatís going on. heís not overfed and never has been, and iím not seeing any outward signs of disease. heís got some fin ripping, but no cloudiness and decay that usually comes with fin rot. think itís mostly from banging around when his swim bladder was at its worst. iím getting worried that he wonít make it. im very attached to him and have been hand raising him since i was 10 years old. definitely donít want to lose him.
any and all help would be greatly appreciated.