So I've got a  mildly planted  45g tank, have 8 threadfin rainbows had 9 and 3 neon tetras had 8 and a couple of amano shrimp. the tanks been setup for about 10 months, lost a couple of tetras in the beginning during my cycle. Just recently I lost a rainbow, It starting having a small growth inside next to its bum hole, gave it garlic and some ich medication and pima fix, it passed away about 3 days later.... that was two weeks ago, yesterday I noticed a second rainbow with the same problem, I've been googling in an attempt to find whats wrong. Any help would be appreciated before I end up losing all my rainbows...Anyone know what the hell this is? file atached...