National Geographic : 1965 Dec
of many other fishes in the world's oceans and seas. The role of wrasses as physicians of the deep struck me as I dived in Bora Bora's Teavanui Harbor. Castles and cathedrals of living coral reached up from the sandy bottom to within a few feet of the surface. Every where dimidiatus hovered by their clinics, usually working in pairs. Their restless cous ins, Labroides bicolor, seemed unwilling to wait for business, scurrying instead about the reef in search of patients. Doctors on house calls, I thought. Mimics Play Cruel Hoax The benefits that cleaner wrasses bring to other fishes hide a danger for their clients, as I learned one day at Taapuna Pass, a break in the barrier reef off Tahiti. Twenty feet down, before my camera lens, a small fish that appeared to be a cleaner wrasse did a shocking thing: Darting off in a lightning pass, it ripped a feathery gill from a tube worm. I knew that cleaner wrasses did not behave that way. A flash of fierce-looking teeth solved the mystery. What had seemed a harmless cleaner was actually a wolf in sheep's clothing, the saber toothed blenny, Aspidontus taeniatus. This blenny is a diabolically clever mimic of Lab roides dimidiatus. It not only duplicates the cleaner wrasse's coloring but even imitates its comical dancing approach. Once within striking distance, however, the blenny drops all pretense and attacks, tearing off a piece of fin or flesh. Adult fish usually spot the im postor and chase it away. Juveniles must learn through painful experience to distinguish licensed practitioner from quack. The late Conrad Limbaugh, an ichthyolo gist who studied cleaner fishes in both Atlan tic and Pacific Oceans, once watched a single cleaning station for six hours and saw 300 fish being groomed. Multiplied by all the cleaners in all the oceans, the extent of sym biotic doctoring staggers the mind. Some authorities believe, as did Mr. Limbaugh, that cleaning represents one of the basic and most important relationships in the world community of fish. THE END Razor teeth bared, a vicious moray eel lurks in its coral lair while a two-inch-long juvenile Labroides dimidiatus scours its head. Young cleaner wrasses stay under ledges and coral heads; when older they ven ture out to set up cleaning stations. 873 Deceptive mimic of a cleaner wrasse, the saber-toothed blenny, Aspidontus taeniatus, adopts the coloration and movements of Labroides dimidiatus.When other fishes ap proach for cleaning, the blenny takes a bite. Fins aflutter, a juvenile Labroides bicolor only three-fourths of an inch long approach es the author, fearlessly offering its services.