Cave Polyps?

[Maxpcf]

I dove the Nicholson tunnel today in peacock and noticed a significant amount of translucent polyps, similar to what you would see on coral.

They appear similar to the image below, but with a narrower stem and fewer tendrils (total length 2cm). They are primarily affixed to hard materials (rock) and appear in significantly greater density and prevalence in the Nicholson tunnel than in other parts of the cave(perhaps related to the greater amount of detritus there), although I noticed them in other parts as well.

Anyone have any idea what these are?

[jason]

I'm speculating because I haven't seen them (but am going to make it a point to check them out when I have a chance) that they could hydroids (based purely on the description of what they look like).

[Confuted]

We noticed something similar to your description at a cold water site. We collected a sample and got an ID from a biology professor, who said they were stentors.

[cmint]

google freshwater hydra, tried to paste the wiki link but it didn't like the parentheses in the link


might be hydra. I get them in planted aquariums from time to time.

[FW]

From the Wiki page. Click on image to see it larger.