I have had a black molly in my tank for about one month. My tank is only 6 weeks old. He seems healthy and has been growing, but lately the tip of his large fin on top of his body has turned yellow. Also the scales on the side of his body have turned white. This does not resemble "ich", as I have seen pictures of it. Does anyone know what is going on? By the way all of my water tests have been good for about 10 days, but before that I had high nitrites for about 2 weeks.
black molly with yellow stripe.
- Thread starter habinero
- Start date
How old was the fish when purchased? There ar color morph mollies, and sometimes they change color as they mature. If the color changes include a change in texture, it could be a bacterial infection from the high nitrites--nitrites and ammonia reduce the fishes ability to get oxygen from the water, and stress the fish. Water changes would have helped. But, at this point, keeping the water clean and monitoring the patches for changes is your best bet. Never medicate until you know what you are treating!
I with Orion Girl on this, it sounds like your fish is just changing. There are many color morphs out there that have mixed with each other that it is hard to tell what you are buying anymore. But as the fish grows older they will start to change colors and slowly morph into the fish they will be. 
I have many cream and black molly fry right now that are slowly morphing to their adult colors. This is very normal for fry/young adults.
jim
I have many cream and black molly fry right now that are slowly morphing to their adult colors. This is very normal for fry/young adults. jim
