What is this!?

[fatpuffer]

Is it a bristleworm? Good or bad? It is inside one of my rocks right now.
It is beside the grape caulerpa in the centre. Its pinkish orange.



Thanks.


js

[Delphinus]

Yep, bristleworm. Is good, ya ya. Well, mostly. When you lift a rock up and there's one of these under your thumb you might curse them a little.

There are a few exceptions where bristleworms are a problem (i.e., seahorse tanks), but for the most part they are harmless detritivores that clean up in your tank.