Meet the Hawaiian cleaner wrasse “the fish dentist”

Do you know that the fish here in Hawai‘i go to the dentist on a regular basis to have their teeth cleaned? From large sharks to young yellow tangs, they all get free dental work, but they must go to the dentist’s office. We call their office a “cleaning station,” and the dentist is a Hawaiian cleaner wrasse.

This small, colorful fish has a territory on the reef, and when it is ready for clients it darts above the reef back and forth, flashing its bright colors. Most divers have seen this fish due to its bright-yellow, blue and purple color, but few people actually know much about the cleaner wrasse. Sometimes there will be two to three cleaner wrasse above one coral outcropping and 10 to 15 much-larger fish waiting in line to have their teeth cleaned. When the larger fish want a cleaning, they remain still right above the cleaning station and change colors. They also extend their fins and open their mouths. This tells the cleaner wrasse that they want a cleaning.

The tiny cleaner wrasse will go right into the larger fish’s mouth or gills and remove parasites and mucus right off of the sharp teeth, much like our human dentist uses a dental pick to clean plaque off of human teeth. The large fish could easily eat the cleaner wrasse, but they don’t because they know if they don’t get their teeth cleaned they could get dental disease and not be able to feed.

It is truly an amazing sight to sit and watch as the large fish are very patient and will wait their turn to get their teeth cleaned from this very-tiny marine dentist. I have seen a six-foot shark patiently waiting behind several foot-long surgeon-fish to be cleaned, and I have never seen a predator fish take advantage of the situation. It is like they all know how important this little fish is to the entire coral-reef ecosystem, and all hunting activity stops anywhere near the cleaning stations.

As soon as the fish being cleaned feels its mouth and gills are now nice and free of parasites, the fish will go back to its normal color, letting the cleaner wrasse know it is done with the dentist appointment. Then the fish just zooms away and a new client comes in.

You can see the Hawaiian cleaner wrasse in action in the underwater educational movie “The World’s Guide to Hawaiian Marine Life” at underwater2web, and we will soon have all of my Hawaiian marine-life pictures and movies up on a phone app so you can identify and learn all about our amazing marine life while sitting on the beach.

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Terry Lilley, a marine biologist, lives in Hanalei. His websites include underwater-2web.com and gofundme.com/5urrm4zw.