The first three pics are now and the last two are a few weeks ago. Sonic my plakat koi has been looking stressed lately, has clamped fins, and seems to have fin rot. How do I fix this besides constant water changes and IAL? I’ll try those out but in my experience they aren’t the most efficient. Idk tho, this guy swam up the filter intake a few months back and I did do constant water changes and he healed from missing scales and ripped fins. I’m just wondering why this even happened in the first place. I’ve haven’t changed pretty much anything in routine and the parameters, and temp are good. There’s no ammonia, no nitrites, and 10ppm nitrates. Ph is 7.5. He has a filter heating the tank to abt 80 degrees. He lives in a 5 gallon with a hang on back filter with low flow. He has a few Java ferns, Anubias, red root floaters, pothos, and ludwigia. I’ve always had a really bad mulm problem in the tank but haven’t thought much abt it since parameters stayed good. I do weekly water changes of 25-50%. I use seachem prime. I use api master test kit to test water. He eats frozen bloodworms, omega one betta pellets and occasional flakes of the same brand. Anything helps, but in the meantime I will be doing lots of water changes. If anyone has advice on how to prevent this or how it happened, the help will be greatly appreciated.