# Marine Aquariums > Marine Fish >  Phyllodesmium briareum nudibranch

## Gary R

Had one of these for around a year now It's spectacular!

Beneath that glorious mass of writhing tentacles is a tiny sea slug getting on with his/her hermaphroditic day.....the one I have got is a big one at about 2.5 cm (an inch) long now, others are less than half that if you can get one.

Found out a little bit about them but not much out there.......

Being an aeolid, _P. briareum_ lacks the gills found in many other nudibranches. Instead, they do all their breathing straight through the skin, but particularly through those wonderful tentacles which are known as cerata.

_P. briareum_ spends the day feeding on various kinds of soft coral, but they also have a whole other food source at their disposal

_You can see that they have four long tentacles on their head
_ If you look closely, you can see a kind of stripy, Woodcut pattern on the slug's skin. These are single-celled plants called zooxanthellae, which live in specialised ducts in the digestive gland. They do their photosynthesis thing and provide sugars for _P. briareum_, and in return they get a safe place to live.

 Would you have thought _P. briareum_ is a master of mimicry? Their specific name _briareum_ comes from Briareos, one of three Greek storm giants who each had one hundred hands and fifty heads. Can you imagine that? So long as they were all of one mind, they could get _so_ much done in a day! It'd be terrible if there were disagreements, though. I have enough trouble actually DOING the things I want to do - and REALLY wanting to do the things I think I SHOULD want to do - without outright factionalism and political intrigue going on among my heads.



Image: Heike Wägele & Annette Klussmann-Kolb
_A big arrow points at P. briareum. Above is two polyps of the coral B. violacea_


Anyway, _P. briareum_ doesn't look all that much like a storm giant, but they do look a lot like a soft coral of the genus Briareum. Specifically, _Briareum violacea_, which is just the kind of coral it might eat. Rude!

 Most aeolid nudibranches are able to swallow the stinging cells of corals, sea anemones or jellyfish and move them into special sacs at the end of their cerata for use in defence. _P. briareum_ doesn't do this because the stings of the soft corals they eat aren't particularly impressive. Instead, their cerata end in glands that produce horrible sticky stuff to deter predators. The cerata can even drop off and wriggle around, hopefully distracting assailants for long enough for the slug to escape.

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