black formation

[MozartOwner]

Hello, I'm at a loss. This black moss like stuff keeps showing up in my tank. At first I thought "% water changes aren't keeping up, I have to clean the entire tank" but I cleaned it two days ago. Absolutely Perfect. Put Mozart in it yesterday after checking the water, could not be more perfect. Mozart loved the deflector I made for him and the new set up. This morning black film in the corner and near a stump. Any good reason? Should I be worried?

[Oldfishlady]

Can you post a pic?

[secuono]

Might be black hair algae, that stuff is annoying. But if you keep pruning the tainted leaves and make sure the filter is also scraped clean of this stuff, you can get rid of it.