I just noticed that one of my cherry barbs (I got 6 a few days ago) has a weird red spot on the side of it, not near the gills or the fins. The 6 cherry barbs are the only fish in the tank and it's a 20 gallon. There are 2 males and 4 females; it's a female who has the red spot. It just looks like discoloration almost, but it definitley wasn't there when I first got her. She's the biggest female by quite a bit actually, and also a bit bigger than both the males. I have no clue what caused it, the only thing I can think of is the fact the males were chasing all the females around the tank trying to mate with them. Maybe one of them nipped her or something? I could really use some help... I can't find anything online about it.