PEACTICAL USE OF FISH 403 



In the southern United States for many years intelligent persons here and 

 there have introduced fish into water tanks for this purpose. Mr. E. A. Schwarz 

 found in 1895 that at Beeville, Texas, a little fish was used for this purpose. 

 The fish was called a perch, but its exact specific character is not known. Prior 

 to 1900, Mr. F. W. Urich, of Trinidad, wrote the Bureau of Entomology that 

 there is a little cyprinoid, common in that Island, which answers admirably 

 for the purpose. In a letter to the Bureau of Entomology Mr. J. B. Fort, of 

 Athens, Georgia, writes that about 1854 his father. Dr. Tomlinson Fort, living 

 at Milledgerille, Georgia, found that mosquitoes were breeding extensively in a 

 cistern owned by certain livery-stable keepers. They refused to use oil upon 

 their cistern, and Mr. Fort was instructed by his father to catch some small fish 

 from a creek nearby and place them in the cistern. About a dozen or more 

 small fish were so placed and in a day or so all of the larvae were destroyed. This 

 instance is mentioned as indicating the early use of fish on a small scale in 

 cisterns. 



In " Mosquitoes " (1901), Howard recommended the practical use of stickle- 

 backs, top minnows (Gamhtisia affinis and Fundulus notatus) and the common 

 sunfish or pumpkinseed, and these fish, especially the top minnows and the sun- 

 fish, were used with success in a number of instances in small ponds. An in- 

 stance has been described in a letter to the Bureau of Entomology by C. T. 

 Anderson, of Anderson, Washington County, Florida, who wrote that he had a 

 spring on his place that swarmed "with mosquito larvae in the summer time. He 

 got about a dozen top minnows and put them into the spring without telling the 

 rest of the family. In a day or two a member of the family remarked that there 

 were no wrigglers in the water. Mr. Anderson verified the observation, and 

 after many months was able to state that no mosquito larvae had been seen since. 



The common goldfish proves to be an excellent mosquito feeder and during 

 the summer of 1901 Mr. J. Kotinskj^, of the Bureau of Entomology, conducted 

 a series of laboratory experiments with goldfish in an aquarium. He found they 

 were voracious feeders on mosquito eggs, preferring them to larvae. He further 

 noticed that the fish, after taking several larvae into the mouth, would eject 

 some of them. Further, he found that in a large Jar containing four goldfish and 

 many hundreds of mosquito larvae, a few of the larvae succeeded in transforming 

 and emerging as adult mosquitoes. The food supply was evidently in excess of 

 the capacity of the fish. 



At an earlier date than this Mr. H. W. Henshaw, of the Biological Survey of 

 the United States Department of Agriculture, was staying at Fruitville, near 

 Oakland, California. The house was badly infested with mosquitoes. He found 

 the source of supply to be a lily pond about 7 x 12 feet in size and fully 3 feet 

 deep, which was fairly swarming with larvae. He got a half dozen goldfish from 

 San Francisco and put them in the pond. The following day they were so badly 

 bloated they could hardly swim, and in a few days there was not a single larva 

 left. The fish bred in the pond and from the time of their introduction there 

 was a very marked decrease in the number of mosquitoes in that locality. 



27 



