I've recently moved my Aquabid orchid male in to the QT tank for unknown tail damage while living in my heavily planted tank. His tail is quite frayed, although he shows no signs of fin rot. As a side note, his all-black coloration has turned red in some areas, but none that have mysteriously dissapeared. That may not be relevant, but I wanted to give all the information I had.
A few minutes ago I fed him (and the female whose also in the tank) and he did the oddest thing I've ever seen a betta do. He ate his Omega One pellets without hesitation, swam idly near the top, and then expelled/coughed a white slimy fuzz looking substance from his gills. There was quite a substantial amount of it, too. There doesn't appear to be any more in there from what I can see, and he appears fine, although not terribly active.
The only other detail I can provide is that the tank is currently being treated with Methylene blue and a light dose of aquarium salt to aid in the recovery of his fins and combat the unkown illness.
Anyone have any ideas as to what this could be, or suggestions on how to combat it? I'm beyond baffled, and beginning to become worried. Thank you very much in advance for any insight offered.