Unknown marine organism

[Mr31415]

Found another weird thing in my reef aquarium. It attaches to the live rock / coral and seems to be filter feeder. I did discover nematocysts on its tentacles so it seems to sting its prey. I also found diatoms in its stomach. They seem to be colonial as I have never found them alone.

First a (close to) 1:1 macro shot of the organisms in their natural environment:

Under the microscope under dark field illumination (4x) they look quite different:

A single polyp with a 10x objective, dark field:

41-image stack with 10x objective, 1.6x magnification, DIC

Single image, 20x objective, DIC

Finally, to show the contents of its gut, here is a photo under fluorescent excitation (UV/Blue), 40x objective. The red stripes are diatoms, not sure what the green blob is and also not sure why its oral disk fluoresces yellow.

 

[Ambition]

Colonial hydroids maybe. I had some, but they were brown in color when looked at in person without a microscope instead of clear like yours are.

 

[jroovers]

Looks like hydroids to me as well.

Unbelievable shots! Those are just incredible.

 

[biodegraded]

I love your work. Great shots. My first thought was hydroid as well, though it's been 40 years since my zoology clases.