The following polychaete worm, probably a Nereid, was found in our deep sea mussel tanks. Often times we will collect a bunch of mussels in a scoop which results in gathering some other rare deep sea creatures and their larvae. Our last collection of the mussel Bathymodiolus childressi from the Gulf of Mexico was in Fall of 2004, from a depth around 600 meters. This worm has been living in our aquaria for at least 4 years.
One interesting point is that these mussels have methanotrophic (“methane feeding”) bacteria in their gills. We only feed the aquaria methane, which is bubbled into seawater. This supports a whole microcosm in the aquarium including this worm and the mussels, but also several species of snail, shrimp and crab. I’ve even seen a nemertean and sipunculun worm in there!
Here is the anterior (head) portion. Notice the cirri and palps!
I took these pictures with a dissecting microscope under seawater with an Olympus digital camera through the trinocular.