False Clown anemonefish with Cymothea.

False Clown Anemonefish with Cymothea.


We have made quite a few posts about this little beastie in the past, but we still get a lot of questions about this critter – in our most recent newsletter there was a picture of a False Clownfish with Cymothoa in the mouth…  We even had a reply asking if it was a Denise Pygmy Seahorse being eaten, which just goes to show how many people come to Lembeh and miss out on this little guy.

Cymothoa are parasitic crustaceans which live inside the mouth and gills of fish.  Cymothea exigua is famous for holding on to the tongue of the fish and eventually causing the tongue to atrophy through lack of blood, leading to the Cymothoa replacing the tongue. The fish continues to live a ‘normal’ life with a prosthetic Cymothoa tongue.

The above is the accepted academic description of what one of these little beasties is, however we have noticed that the tongue in the Clownfish does not atrophy and is still normally sized under the parasite.  When you look at the clownfish in one location over the period of years, they almost constantly have parasites, and are always producing eggs, so they are still highly fertile.  Which is pretty amazing really, when you consider how much time the fish with this parasite spend yawning and looking very uncomfortable!

Hopefully next time you’re in Lembeh you can get to see one of these parasites.