My tank is a 30L Biorb and has a betta & 3 platies in it. they all get along fine, with no sign of bullying or anything... but when I first introduced 3 platies into the tank, a similar tear has been noticed on one of my platy. I had initially thought that it has got to be the betta that's bullying ...

Hi everyone, I had a new corycat in my community tank for about 2 weeks now, and today I noticed that he has a section of his tail missing... more of a clean cut than the finrot I've seen on other fish, but regardless, I took him out of the community tank and put him in a large bowl (1G) to treat ...