Curious what are these?

[Myka]

Originally Posted by HaZRaTTy

They are very easily pulled off with a razor just scraping.

Try just pulling with tweezers. Tunicates and sponges are delicate, hydroids have a surprisingly tough tube. If they are just dead hydroid tubes, there is no need to remove them unless you find them unsightly. If they were live hydroids they would be stinging the poop out of the Zoas.