242 DESCRIPTIVE KEY TO BREEDING, ETC. 



Boleichthys) are hard to induce to spawn in an aquarium. The eggs are 

 deposited among the stones of the bottom. The parents should be re- 

 moved. All the Perch family are carnivorous. 



POECILIIDiE— KILLIFISHES (No. 18) 



This large family is almost cosmopolitan. The aquarist, for con- 

 venience, divides the family into two sections ; one, in which the ova are 

 hatched within the female's body and the young born alive, and the 

 other in which the ova are deposited to hatch externally. The first or 

 viviparous group (all of which species are marked with a V. after the 

 family name in the list) is separated into five sub-families: the Anable- 

 pinae, in which the anal fin of the male is modified into a long tubular 

 copulatory organ; the Jenynsiinae, in which the male's anal fin is es- 

 sentially the same; the Poeciliinae, in which the male's fin is trough- 

 shaped rather than tubular; the Characodontinae, in which the entire 

 anal of the male is not modified into a long organ, but the first few rays 

 are stiff and short and are separated from the rest of the fin by a notch, 

 and the Phallostethinae, in which the male's ventral fins are modified 

 into a singular process beneath the head. The egg-laying or oviparous 

 division is comprised of three subfamilies: the Cyprinodontinae, which 

 includes the Cyprinodons, etc., the Fundulinae which includes Fundulus, 

 Oryzias, etc., and the Adrianicthyinae found only in Celebes. 



The viviparous species are easily bred. The gravid female should 

 be placed in a large jar with thick, bushy Nitella or Riccia on the light 

 side. The young, when born, seek the light, and are protected by the 

 plants from the cannibalistic parents. Excellent fish-traps are now 

 made, obviating the necessity of the above treatment. (Some of these 

 are shown on pages 122 and 123.) 



In the egg-dropping group the breeding habits are more diverse. Of 

 the species herein enumerated the breeding is as follows : For practical 

 purposes A. sophiae, J. jloridae, all the Funduli except F. caeruleum, 

 the Panchaces, and Rivulus may be under one head. The pair should be 

 kept separated for a week or two and fed on nourishing food. Then 

 place them together in a warm, sunny tank with thick floating Utricul- 

 aria or Riccia. Spawning should soon commence. Leave the pair to- 

 gether a day, separate, and repeat, removing the egg-filled plants to a 

 hatching jar and replacing with new. Feed young on small daphnia. 



In Oryzias, crystal-clear eggs are expelled and fertilized and hang 

 in a tiny cluster from the female's vent. In moving about, the eggs are 

 brushed off and adhere by a fine filament to the plants. The hatching 

 and care are the same as for Panckax, etc. 



Except Belenesox and Gambusia aff., the Killifishes are peaceable 

 citizens. 



