What is this, from St Lucia?

Dec. 2015 - St Lucia. There is some yellow tube sponge covered by what in this image?

http://www.cjcphoto.net/caribbean2015/images/151216-064118-19-76-d810.jpg

Nobody? I was thinking this was some form of reproduction of ... something, but really haven't a clue where to start to id this.

My guess would be hydroids.

Never heard of them before, but a bit of research says you are probably right. Thanks!

Hi,
can as well be a larval stadium of a medusa / jellyfish....
They look very simmilar to hydroids, or better they belong to the family ;-))
The larva sits on the ground or every surface they can grow on, until they produce a polyp.

I have two different species in our saltwater tanks ;-))

Regards,
Wolfgang