Hi everyone, I am posting because recently one of my Columbian Tetras has developed some type of growth on its tail. It looks pinkish red and the rest of the tail has lost its red color. A couple weeks before I had noticed the fish's belly was exceptionally large, but I passed it off as pregnancy because I saw no pine-coning of the scales. Please help me identify and fix the problem with the fish. I will post the image below.