Help!! My molly fish has weird green stuff growing all over it!


New Fish
Dec 10, 2017
Hey guys, I need some help. My molly fish has weird green stuff growing on its fins. I noticed this when my Molly fish went really close to the lights at the top of the tank, and when the lights shone through her fins it exposed this weird green stuff on her fins. What is this stuff? Is it harmful? If so, what medication do I have to buy? If you need pictures just tell me. Thanks!


Superstar Fish
Jan 11, 2013
East Aurora, NY
Any recent additions to the tank that could have brought in an illness or parasite? This includes live foods.

The reason I asked about your water parameters is it's high nitrates can cause issues like you describe. Nitrates creep up daily and are only reduced by doing water changes of 50% or more per week.