Hitchhiking anemone? Is it?

[Lady.of.Babylon]

I put some plants in my tank and then these started showing up... found about half a dozen of them. What are they exactly? And will they bother my pipefish and sexy shrimp.

Yes they do seem to sting.

[Sniperhank]

Majano anemone. Pest glass anemones. Get rid of them by injecting them with a product like aiptasia-x or joe's juice. Breaking or scraping them will case them to 'shatter' and create additional anemone to grow from the shards.