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CRITTER: Meet the banded coral shrimp, the underwater dentist

Most divers and snorkelers here in Hawaii have seen the banded coral shrimp. This super common marine invertebrate is usually seen during the day hanging upside down in a small crack or cave in the reef. You often just see the shrimps white tentacles poking out of the cave and when you dive down and look up close you can see their bright red banded body. Normally these small shrimp are in pairs and will defend their territory.

The shrimps cave acts as a dental office and there is almost always a moray eel close by that needs to visit the dentist. Most morays are active at night so the shrimp is usually open for customers during the night hours where it is less likely to get eaten. A moray eel will slink into the cave that has a waiting pair of banded coral shrimp ready to do dental work on the moray. This is super fun to watch and shoot video of because it shows how many marine life species help each other in a beneficial way.

The shrimp dentist does not do house calls for the moray eel because it may be eaten by a goatfish along the way so the moray must visit the shrimp dental clinic. When the eel arrives the pair of shrimp come out and greet their new customer. If the eel wants its sharp teeth cleaned it will open its mouth wide and remain very still. This lets the shrimp know that the eel wants its teeth cleaned and is not looking to make a meal out of the shrimp! The small shrimp crawl into the open moray eels mouth and pick parasites off of the eels gums. These tiny parasites are good food for the shrimp and will gladly be given up by the eel. The entire shrimp dental visit may last for up to an hour. If the eel gets desturbed and has to leave it closes its mouth quickly but keeps it open enough for the shrimp to dart back into their safe cave. The eel does not want to harm its private dentist because it wants to come back to get cleaned from time to time.

20 years ago when I first shot video of the shrimp cleaning the moray’s mouth I had a funny idea. I wondered if the shrimp would clean my teeth. Heck, free dental work! Since I knew how to act like a moray eel I held my breath of which I can do for five minutes or so, then I dove down and laid peacefully at the entrance to the shrimps office and slowly opened my mouth. Well, it worked! The shrimp came in and immediately started pecking around in my mouth looking for dinner and it really tickled! I had a super hard time keeping from laughing at the unusual experience. After my dental work was done I went back to shore and got my underwater movie camera and a good friend that also needed some dental work! We both went back to the shrimp cave and my friend opened his mouth and the two shrimp jumped right in for a cleaning. I shot a video of the whole event and posted a still pic of my friend with the shrimp in his mouth on social media and the picture went viral!

I visited one special shrimp dental office often out at Koloa Landing in Kauai and the shrimp came to know me as a regular customer but the shrimp became agitated and confused because I brought along my video camera to film them for one of my movies. I got some great video of the shrimp coming out of their cave and trying to clean the camera lens! I guess the shrimp looked at the camera lens as an open mouth ready for cleaning but they could not find the mouth and get in! Who knows, maybe these shrimp have very bad eyesight!

You can see the underwater shrimp dentist in action in my movie series on YouTube at Underwater2web and we will be making a whole movie about “cleaner fish and shrimp” . I will also be posting hundreds of marine life pictures and movies up on my kid friendly Instagram at terry.lilley. In the meantime you might have fun while out snorkeling and see the shrimp peeking out of a cave. Dive down and smile as the shrimp may just be open for business and in need of a nutritious meal. Mother Nature is pretty fun to be with if you choose to do so.


Terry Lilley is a marine biologist living in Hanalei Kaua‘i and co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawaii go to
Source: The Garden Island

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