Anyone Got a Clue About this Thing??

[Spalding]

See the spot on this Copperband? It is actually on his pectoral fin. Anyone know what it might be? I know the picture's not that great but, believe me, it's not really easier to see with him flapping it around all the time! He's had it for a couple of weeks now. It actually has a little thickness to it (maybe half a mm). I don't want to remove him and put him through the stress of removing it or treating him if it's just something stuck to his fin. He seems perfectly happy otherwise. Thanks for any input.

 

[ThRoewer]

Could be something like a fish louse. You could try to remove it with tweezers.

Also, judging by the whitish patches on the fish's skin it has either ich (just fallen off), Brooklynella or velvet. I'd have a closer look at that first.