Hello. I have noticed a white clumpy spot on one of the skirt tetra fins about a year ago and weirdly enough, it didnt spread until recently and only to the other fish of the same species. It doesn't look fussy and only on fins. I have been treating them with Maracyn in combination with IchX and got no result from it. Now I have been doing salt bath with 1Tbsp per gallon for about 2 weeks and still no result. Some of the white clumps did go away but they leave behind red patches on the tetra fins. I would love to get some idea on what this is and how can I treat it. Below I've attached a link to the video.
Link to Video