It is really hard to get decent pictures of it but I would describe it as a reddish brown worm looking thing that does not move apart from with the current and is growing although slowly. It is organic in texture and only seems to be growing on the wood. I do tend to let algae grow on the wood as I think it looks ok. Hopefully the pictures will give you a better idea. Sorry about the photobombing fish.
1.6 MB Views: 52
981.2 KB Views: 49