ID Help

Ian Baxter · Oct 18, 2026

I’m trying to figure out what these are so I can create a good plan of action to get rid of them. I have taken the large rock out, soaked in peroxide for about 10 minutes, scrubbed and rinsed it clean and everything came back. I also have it growing on the sand. I think it’s either sarcothelia or colonial hydroids but I don’t know a way to tell them apart

Decamicron Labs · Oct 18, 2026

Definitely not colonial hydroids. It is some octocoral, however, I wouldn't be comfortable assigning a genus name until one could look at sclerites from an expert at least.

Tahoe61 · Oct 18, 2026

Dreaded clove polyps.
https://www.reef2reef.com/threads/remove-clove-polyps-for-good.967400/

Ian Baxter · Oct 19, 2026

Decamicron Labs said:
Definitely not colonial hydroids. It is some octocoral, however, I wouldn't be comfortable assigning a genus name until one could look at sclerites from an expert at least.

Thank you. Any way to get rid of them or do I just need to toss the rocks?

Decamicron Labs · Oct 19, 2026

Ian Baxter said:
Thank you. Any way to get rid of them or do I just need to toss the rocks?

I have had success with flubendazole and fenbendazole in fish-only tank for colonial hydroids and I have seen reports of it being used on octocorals with success. I don't know how they will affect your hard corals. These two drugs work by blocking beta-tubulin extension which prevent regular metabolism from occurring. This eventually starves the cell. However, some hydroids have stolon basal cells that do not have much metabolism, and could potentially persist and return later. I don't believe octocorals will have this problem, but I could be wrong. You will also need to run carbon religiously after since the drugs will bind to rocks I believe and could pose a threat to your snails. I would also suggest flubendazole. They are part of the same drug family but flubendazole is supposedly much safer to you.

Tossing the rocks is possible, but you have to be careful about your nitrogen cycle. That is where nitrifying bacteria live. Just feed less for a month after.