SELECTION OF FISHES 31 



mental fishes they have the advantage of being small, 

 but not much is known about them as an aquarium 

 fish. It is likely that they would reproduce in captiv- 

 ity. 



The grass pike (Esox americana) occurs in streams 

 and lakes of both the Mississippi and east coast drain- 

 ages. The greater part of its diet is fishes. It is a good 

 choice as a representative of the pike since it reaches 

 maturity at 8 to 10 inches. It is questionable if this fish 

 will reproduce under aquarium conditions. However, 

 it could very likely be spawned by use of pituitary 

 preparations. 



Cyprinids 



The characins are small fishes of South America, 

 Central America and Africa. They are widely avail- 

 able in the United States inasmuch as they are both 

 imported and raised as ornamental fishes. A great 

 variety is available, but perhaps the most popular and 

 the one about which most is written is the neon tetra, 

 Hyphessobrycon innesi. One may find considerable 

 literature on the care and culture of this group of 

 fishes in books and periodicals deahng with "tropi- 

 cal" fishes. The reader is especially referred to Exotic 

 Aquarium Fishes (Innes, 1938) and the Aquarium 

 Magazine, The Aquarium Pubhshing Co., Norristown, 

 Perm. 



Characins favor a temperature of 75° to 80° F. They 

 do quite well on a balanced ration in dry, powdered 

 form, but an occasional meal of hve food is beneficial. 

 Characins can be fairly easily spawned in captivity. 

 Higher temperatm-es (80° to 85°) and good food are 

 conducive to spawning. As is the case with most of the 



