Weeping willow Dying?

[Zane5225]

Toadstool in the top left has been happy in my tank for over 1 and a half years. But about two weeks ago it closed and looked like it was maybe shedding but now the flesh on parts of the edges is melting. Any suggestions?
Below is a before and after video.

 

[Mr. Mojo Rising]

The water seems to be barely moving, toadstools like good flow, they need it to stand up straight and to help them shed and to bring them nutrients. Put it in a spot with good random flow patterns, then you'll see it perk up.