AQUARIUM FISHES 345 



chambers, it soon dies. Thus the labyrinth fishes are well 

 suited for the aquarium, being able to take oxygen from 

 the air jas well as from the water. 



They are hardy fishes, but most of the species, especially 

 the Fighting Fishes (Betta), require a temperature of at 

 least 68° to 70° Fahrenheit, and often are kept in heated 

 tanks. Generally they are pugnacious and vindictive, and 

 must be kept singly or in pairs. They are easily fed, readily 

 taking prepared foods, which should be supplemented with 

 occasional bits of scraped raw beef, chopped worms, boiled 

 yolk of Qgg and living Crustacea. 



The breeding habits of these fishes are curious and most 

 interesting. At the approach of the season of reproduction 

 the male goes through an elaborate courtship, spreading his 

 brilliant fins to their utmost extent, and scintillating with 

 intense color. Soon the female responds, and the male com- 

 mences the construction of the nest. This is composed of a 

 mass of air-bubbles coated with a viscous substance secreted 

 by a special gland, which causes them to adhere together. 

 The bubbles are piled up in the form of a low cone, which 

 floats on the surface of the water. Oviposition soon takes 

 place, and the female must be removed at once, for the male, 

 assuming charge of the nest, will not tolerate her presence. 

 After two or three days the tiny young hatch and are 

 carefully guarded by the father, which gathers up in his 

 mouth any which fall from the nest and carefully returns 

 them. Soon after hatching the young begin to leave the 

 nest and move about in search of food. When this stage is 

 reached he, too, must be removed, for parental affection 

 vanishes, and he regards his offspring merely as an admir- 

 able addition to his menu. The fry feed, as do the young of 

 most other fishes, on protozoans, and later on small Crus- 

 tacea and powdered dry food. Care must be taken not to 

 feed Crustacea until the young are large enough to eat them, 



