Anyone know what these are? They appear all over my tank. On the walls, rocks, sump, overflow, fans. They are hard. Don't seem to be bothering anything.
Tank is a mixed reef, 3yr old. Lots of coraline algi.
Yep, vermetids. Almost every tank will get them but they can be a problem if the numbers get out of control. The feeding 'nets' they cast out can irritate some corals. I've lost a lovely acan colony to them and a big beautiful blasto has some dead polyps too. Now I just crush the ones that get too close to something I care about.
You can put a dab of superglue on the end and it will take care of it. Breaking them off isn't really a 100% guarantee of eliminating it sadly. The superglue works like a champ though.