Flap Like A Wrasse

Yellowtail Coris Adult/Juvenile, Photo Courtesy Dr. Jack Randall

Several times per week we get asked about Nemo, the cute little star of the Walt Disney movie “Finding Nemo”.  Unfortunately, the Clown Fish did not take hold in the Hawaiian Islands, but the closest thing to him (at least looks like him) is the juvenile phase yellowtail coris, which is a wrasse.  The wrasse family is quite large and very diverse.  They vary in size and shape with large lips and protruding front canine-like teeth and nodular to molariform teeth in the throat area.  Their scales are smooth edged and most wrasses are brightly or complexedly colored. Juveniles have very different coloration from the adults, like the pair in the above photos.  This can be confusing to the average diver who may not know this fish family very well.

According to the researchers, sex reversal from female to male may be true for all wrasses in the family.  The change is generally accompanied by great color transformations ending with the male more colorful than the female.  Many species have identical colored male/female in the first color phase (initial phase).  These spawn in male dominated aggregations.  The release of sperm and eggs takes place at the peak in an upward rapid rush.  Terminal males will then establish sexual domination and spawn with individual females in a harem.  Should he die, or be eaten, the largest female in the group will absorb her eggs, develop sperm and become the dominate male.  But, unlike human females, she cannot change her mind and reverse the process.  She will stay a male for life!

Wrasses are diurnal, i.e. daytime feeders with smaller animals burying in the sand for protection while sleeping.  Larger ones will seek shelter in the reefs.  All wrasses are carnivorous, most feeding on hard shelled inverts like crabs, sea urchins, mollusks, hermit crabs, and brittle stars, which they crush with their powerful throat dentition.  Some of the larger fish will turn over rocks to get to their food hiding underneath.  According to Dr. Randall, the species Anampses strike forcefully the bottom with their projecting teeth and suck in crustaceans and mollusks along with debris and sand.  Some feed mainly on fish and others, zooplankton.  It is amusing to note that the ones with really big lips will feed on coral polyps.  In an earlier posting we discussed the cleaner wrasse, hinalea, who is a parasitic eater, also taking in skin mucus.

I get great joy watching wrasses swim because they do so mainly with their pectoral fins, flapping madly and using their tails only when they need a burst of speed.  Most stay close to the coral reefs, but not the razorfish and knifefish.  They have compressed bodies and thin foreheads enabling them to dive into the sandy bottom for protection.  In Hawaiian waters, the wrasse family (Labridae) is represented by 43 species making them larger than any other shore fish family.

If you are coming to the islands and plan on snorkeling it may be a good idea, for those who want to learn some of the reef fish, to pick up a copy of Dr. Randalls’ book “Shore Fishes of Hawaii”, available in most Longs Drugs, ABC Stores and also in our local aquarium gift shop.  This book is full of color pictures and will make learning fun.  It is this author’s opinion, everyone should get out on the water at least once when they arrive.  The Hawaiian Islands sit in the middle of the sub-tropics and are surrounded by beautiful beaches and coral reefs.  To really get the full well-balanced enjoyment of your vacation, please plan on getting wet.  Let the children know that although Nemo lives in Australia and other places, they can look for his double, the baby yellowtail coris.

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