I have this brown stuff growing on the rocks in my tank. It is underneath we're there is low light conditions. I'm thinking some type of sponge but really have no idea.
Yep definitely a sponge. They come in all colors. I've had that color and white more commonly than others. The orange ones are really cool. Harmless filter feeder and usually indicative of pretty good water quality.
You've put my mind at ease. I was worried it was something bad with the way my luck has been lately. Lol
I have a rock covered in something similar.. yellow. I thought it was where the large monti cap had been previously positioned and assumed it was part of the underside flesh. I wonder if it's sponge too.
