ZOOLOGICAL SOCIETY BULLETIN 



Numerous species of crus- 

 taceans are inimical to fish- 

 es, and at one time it was 

 reported that the minute 

 fresh-water shrimp, collect- 

 ed in such quantities by man 

 to feed his aquarium fishes 

 with, would actually fasten 

 in numbers upon very young 

 trout and eat them alive ; 

 surely, if true, a case of un- 

 conscious retribution. 



The waters of lakes, 

 ponds and brooks are popu- 

 lous with heetles, bugs, 

 mites, and the larvae of in- 

 sects born in the water and 

 later developing wings — 

 particularly beetle and dra- 

 gon-fly larvae — that prey 

 upon young fishes. Many 



aquatic bugs are armed with sharp and service- 

 able sabres which they use to spear fishes sev- 

 eral times their own size ; the beetles have pow- 

 erful jaws, and seven or eight in unison will 

 attack and devour a live fish ; and the dragon- 

 fly larva is a formidable enemy, with its long, 

 arm-like "mask" bearing on the end a pair of 

 miniature ice tongs, that can be darted out sud- 

 dently to seize an unsuspecting passerby in the 

 shape of fish, tadpole, or brother dragon-fly. 



It has been estimated that a dragon-fly larva 

 will make away with several hundred little 

 fishes in a day, though several dozen is probably 

 nearer the mark. In a test of the capacity of 

 the water tiger (the larva of the predaceous div- 

 ing beetle) in which tadpoles were used, the 

 present writer found that the creature would 

 devour thirty-nine tadpoles in a twenty-four- 

 hour day; and young fishes would, no doubt, in 

 a state of nature, fall prey similarly. The ap- 

 petite of the dragon-fly is much the same. 



A most curious and interesting case of the 

 destruction of very young fishes by mosquitoes 

 was reported some years ago by a gentleman 

 who said that as he was sitting in the shade of 

 some willows overhanging a mountain creek in 

 Colorado, the morning sun fell upon the almost 

 transparent bodies of some young trout — babies 

 still bearing a portion of the yolk sae. They 

 came to the surface every few minutes, and 

 over them circled a swarm of mosquitoes. When 

 a little head reared itself level with the water, 

 a mosquito would light upon and instantly trans- 

 fix it by inserting its bill into the brain and 

 sucking out the life juices, whereuopn the dead 

 trout would turn over on its back and float down 

 the stream. This massacre of the innocents he 



NDFISH {MALACANTHOS PLUMIERI) 



witnessed for half an hour, during which twenty 

 victims were counted. 



A large black spider was once observed in 

 New Jersey catching a fish, which it bit, grip- 

 ped, and dragged out on land. 



Some mollusks are said to eat the spawn of 

 fishes, and fresh-water mussels, as is well 

 known, are parasitic on the fins and gills of 

 fishes in the early stages of their growth. 



In a test once made of the survival of the 

 fittest, between beetles, bugs, fishes and other 

 pond inhabitants, a salamander was seen de- 

 vouring little fishes at the rate of forty an hour. 



Some species of fish appear to have more ene- 

 mies than others. The salmon has numerous 

 foes besides man, — brown bears, seals and 

 wolves, eagles, gulls, terns and mergansers all 

 finding it palatable, besides which trout and 

 sculpins prey extensively upon the eggs and 

 young. 



Sharks rank second only to man as destroyers 

 of cod. 



Jelly-fish capture fishes of various sizes by 

 stinging them with poison nettles, and a species 

 of colorless fresh-water hydra paralyzes infant 

 fishes in the same way. making many a meal off 

 them. 



Among the foes of little fishes, carnivorous 

 plants have not escaped suspicion, though their 

 enmity is believed to be neither persistent nor 

 formidable in a state of nature. Darwin de- 

 scribed plants that, by means of highly special- 

 ized leaves secreting gastric juices, capture and 

 consume small insects — insectivorous plants — 

 and he described the manner in which the blad- 

 derwort. Utricularia vulgaris, imprisons and 



