Any suggestions on what this could be?
Seems like part of its mouth is rotted and there's a small hole, also dorsal fin looks like its way smaller.
Hides most of the time, freaks out quick when you come close to the tank. Always eats though.
Tank water is perfect. Tank mates are 2 other platys, (2f 1m total), 6 rasboras, 6 glow light tetra, a snail and 2 Amano shrimp