1340 



ZOOLOGICAL SOCIETY BULLETIN 



FOUR-EYE FISHES (CHAETODOK CAPISTEATUS) 

 Photographed at the New York Aquarium 



backward to the gill flap. The spot below the 

 dorsal rays stands out clearly^ and one not 

 knowing the fish would naturally mistake the 

 tail for the head. 



The four-eye is one of the most interesting 

 and curious of coral fishes^ and is seen usually 

 in pairs picking at the corals and sea weeds on 

 which it finds the greater part of its food, com- 

 prising small Crustacea and annelids. Swim- 

 ming in and out of the crevices and holes, it 

 will chase an intruder from its feeding ground. 

 Although it cannot harm a larger fish, it will 

 attack one many times its size, bristling up its 

 fins, swimming around and darting at and butt- 

 ing the offender until it leaves. 



A habit of this genus which I have frequently 

 observed is that they will live in and feed 

 around the same hole in a reef for many years. 

 The chaetodons are fearless little fishes and will 

 be found among many other forms, and seem 

 to be respected by them. In fact, the four-eyes 

 are useful to the others in removing parasites 

 from their mouths and sides. I have many 

 times observed them picking at large groupers 



and morays. While in Bermuda I observed at 

 the Aquarium, the four-eye swimming into the 

 mouths of the green moray {Lycodontis fune- 

 bris) and the black grouper {Mycteroperca 

 honaci). When first noticed, I thought this 

 habit was caused by the lack of small crusta- 

 ceans in the tanks, and that necessity had driv- 

 en them to take desperate chances. But why 

 did the larger fish insist, when the little fellow 

 seemed to have satisfied its own appetite? The 

 larger fish maneuvering so as to get in front of 

 and facing the four-eye, would stop and open 

 its mouth. I carried the observation further, 

 removing two of the four-eyes from the tank and 

 placing them in one that contained a number of 

 grunts {Heamulon sciurus), which species recog- 

 nized them at once. The surroundings were 

 strange to the four-eyes, and the pair moved 

 about slowly for a few minutes. The grunts 

 opened their mouths in front of the four-ej^es, 

 but the little fellows paid no attention to them 

 whatever. The next morning I was at the tank 

 early and the four-eyes were still nosing around. 

 A little before noon I returned, and both were 

 busy getting their meal of parasites from the 



