Oranda goldfish with genetic problems?
I'm in great need of goldfish disease expert. Any suggestion/ help is much appreciated. I have a 40 gallon tank with 2 fish in it, a larger red oranda and a black medium lionhead in it. I've had the oranda for 5 years and lionhead for 4 years. Tank temp is 72F, PH at 7.2, Tetra Whisper EX45, Amonia Alert at safe level (yellow), as well as Nitrite, water change every 2 weeks. Around same time last year, the oranda had split/ deteriorating fins problem, paired with swim bladder disorder behavior. I didn't consider it as fin rot because it didn't fit description of fin rot online. He did have few blisters at the end of splitting fins. Yet, I treated him with Maracyn, then Maracyn-2. None of those 2 works but eventually he recovered by himself. Both fish always have nice vibrant color with no missing scale. This year, the same thing happen... but worse. He has been belly-up for almost 3 months now (peas treatment twice, but didn't work), fins are splitting badly, eating but struggling. The 2 fish are happy with each other and they don't fight, not even when the big one is sick. The lionhead, never caught whatever disease it is that the oranda has. So, is it a genetic defect or fish disease? Someone told me maybe he's belly up because his head is too big. The oranda does have huge wen, that seems to be the same size of his belly. Could this be a problem? Is he in pain? I've heard other owner doing mercy kill to their pet fish, but I'm afraid thinking: what if he will be just fine tomorrow as he did last year? Please help, anybody out there. And if I do have to put him out of his misery, how? I hope I don't have to. Any meds I can give him? Thank you again for your help.