can anybody tell me what these weird tubular appendages are which have been starting to pop up in many places around my tank? The have been multiplying in number. My tank was a FOWLR until I added a multi-coral rock in late May/early June.
These things seem to secrete some sort of stringy stuff every once in a while (or debris just clings to them, not sure). Are these things some sort of nuisance organism? What to do?