30 



Aquatic JLitt 



not unknown among these fishes, but the 

 progeny invariably die. It must not be 

 forgotten that the adults, in the aqua- 

 rium, are generally cannibalistc, though 

 seldom perhaps in nature. Therefore, 

 for breeding in confinement, the older 

 fish must be separated from their young 

 or a densely planted aquarium provided 

 for the operation. Among dense masses 

 of plants the young will find a compara- 

 tively safe and sheltered retreat. Consci- 

 entious aquarists place the female, just 

 prior to an expected delivery, in small 

 boxes or glass tanks placed partly into 



Pseudoxiphophorus bimaculatus 



the water of the aquarium. These tanks 

 have holes or slits in the bottom just 

 large enough to permit the young to drop 

 through freely, the adult being retained. 

 If this plan is not followed, place the 

 aquarium near a window, massing the 

 plants toward the light. The young when 

 born seek the light, penetrating the plants 

 out of reach of the parent. 



The young are easy to raise. Their 

 first food consists of infusoria and alg?e. 

 which is present in all aquaria that have 

 been standing for a number of months ; 

 after a few days Daphne and Cyclops 

 may be given. During the winter months 

 the tooth-carps should have a minimum 

 temperature ranging between 60 and 70 

 degrees, Fahrenheit, according to the 



species, but in the summer months they 

 may be kept out-of-doors without danger. 



Under some circumstances females ap- 

 parently about to expel a brood fail to 

 do so. This is a so-called mis-fertiliza- 

 tion. The female, after a few hours of 

 agitated swimming, gradually becomes 

 slimmer, and on the surface of the water 

 appear a number of bright, round spots 

 resembling the "eyes" on bouillon. These 

 persist on the water for several days, 

 and, though the microscope will not 

 solve the riddle, it is known that these 

 "eyes" are over-ripe and dissolved eggs. 

 They consist of a gelatine-like substance 

 that does not subsequently develop. 



It is very probable that many of these 

 viviparous fishes, which are more or less 

 closely related, interbred in their natural 

 habitat as well as in the aquarium. The 

 majority of these hybrids are no doubt 

 capable of developing progeny. Such an 

 interbreeding between Xiphophorus 

 helleri and Platypoecilus maculatus rubra 

 was brought to a successful conclusion 

 by rearing the sexes separately and later 

 placing them together in an aquarium. 

 The resulting hybrids in turn reproduced, 

 the second hybrid generation retaining 

 the characteristics of the first cross. 

 Segregation of the sexes is necessary to 

 induce cross-breeding, as females after 

 having lived with males of their species 

 will repel the advances of others. 



The tooth-carps are natives of South- 

 ern United States, Central and South 

 America, and are found in great abun- 

 dance, both in numbers and in species, 

 in the small streams, brooks and ditches, 

 which they frequent. 



Advertising of character and dignity 

 has much to do with success. 



Fool friends are worse than wise ene- 

 mies. 



