So my betta's finrot got worse while I was treating him with Bettafix. I think that could have been partly a water quality problem. But I discontinued that treatment when I read that it doesn't actually kill bacteria. Then I tried a course of Marineland All-in-one remedy, following the directions. Didn't work. Then I tried daily water changes with 3 tsp/gallon of aquarium salt. Fin rot was still progressing, though slowly. Now I am on day 3 of Tetracycline AND 3 tsp/gallon of aquarium salt. I need to stop the salt treatment or reduce it after the final dose of Tetracycline, because I read he shouldn't be on that high dose for more than 10 days. I know aquarium salt is controversial in the first place, but I don't know who to believe. EVERY treatment is stressful/potentially damages organs, so I don't know. I just know he is SO happy and does not outwardly seem stressed at all. My question is how I know whether to repeat the Tetracycline treatment after tomorrow. I think the increased tearing I see now is a result of the continuous motion of a delicate structure, though I can't be sure. It is possible the fin rot has stopped getting worse, but it's so hard to tell if the progression is just slowed. We are talking super tiny surface area here. There is a red spot on the tear on his upper fin and a red spot on the tear on his tail. By the way, he is mostly transparent except for some dark spots on his body and full body and fin iridescence, so I would know if there were any more red spots than this. This is the most difficult case of finrot I ever remember seeing. I don't remember ever having failed before when I used to keep bettas. I think part of the problem may be his tail was already shorter from it when I got him, but I had no way of knowing at the time since it was the first time I saw him. He has a lot of fin left, but I have been terrified it would spread to his body. So how do I know whether I need to do another course of Tetracycline? I'm assuming I'm supposed to do a 100% water change before repeating. For those who are not completely opposed to the use of aquarium salt, should I give him a reduced dose after tomorrow or none at all? I am really wondering if this is just a salt resistent strain anyway.