One of my black neon tetras may have injured herself although I am not sure how. I do not have any larger aggressive fish. I noticed a red spot on one side a couple of days ago and the fish was swimming in a vertical position. The fish is still alive but hanging in the plants for stability. The spot does look a bit better today but from what I can tell the fish is still having some trouble swimming. I am not sure what I can do to help. I have been doing more frequent water change to reduce possibility of infection. Has anyone run into this situation before? Thanks.