i originally got 3 tigerbarbs for a 14g, one of them died shortly after. i got them together in 2007, and the one started to gang up on the other one when the 3rd died. he nipped him so bad eventually his right fin fell off and is now a dark nub. but he still gets around. hes been like this for about 2 years or so now. its never really changed, but i put them into a 55g tank this december, and the one seems to leave the other alone with all of the extra room in the tank. He has grown to the same size as the other tigerbarb, but just has that nubby little fin. yesterday, i got home to feed them, and to my surprise, the tigerbarb had a balloon looking bubble thing surrounding his little fin. WHAT IS THAT? it kind of resembled those goldfish with the bubble cheeks and eyes. i know that their cheeks/eyes is just a membrane fluid sac, so is this a secondary infection, or is it healing? probably stupid to think it might heal and grow back after all this time, but it did look like the nub was extending and growing the days before the balloon showed on him. it was clear fluid with a tint of blueish gray. and i didnt get a photo of it, also, today its gone. so it mustve gotten popped. any advice about what this thing may have been would be appreciated~