Some kind of worm thing?

[ShietFak]

What is this thing attached to my glass?

 

[vetteguy53081]

Looks like hydroid. Simply take an old credit card and scrape it off into a net and discard. These are capable of stinging nearby coral if given the opportunity

 

[duberii]

I’d guess Medusa worm- some people say they get out of control and then they’re hard to get rid of because they can release toxins when they die (I think they’re types of sea cucumbers actually) but most people I’ve seen struggle to keep them alive

 

[king aiptasia]

What is this thing attached to my glass?

nice sea cucuber

 

[king aiptasia]

I’d guess Medusa worm- some people say they get out of control and then they’re hard to get rid of because they can release toxins when they die (I think they’re types of sea cucumbers actually) but most people I’ve seen struggle to keep them alive

most encountered sea cucumbers got toxins, but they are small and so the amount of poison released is not tremendous

 

[duberii]

most encountered sea cucumbers got toxins, but they are small and so the amount of poison released is not tremendous

True- but some of the infestations I've seen are absolutely insane, and a mass dieoff (even if there were no toxins involved) would be bad news.