SOME FRESHWATER AQUARIUM FISHES 



receptacle and water, much plant life and frequent changes of water being 

 unnecessary. The fish is an air-breather and is not dependent upon the 

 oxygen liberated by aquatic plants. It will live in temperatures to ioo° F., 

 but, on account of its tropical origin, succumbs to those under 38° or 40° 

 F. It is of such lively habit that the aquarium should be kept covered 

 to prevent its leaping out of the water. The sexes should also be separated 

 except in the breeding season, as the full-grown pugnaceous male 

 frequently kills its mate and will exterminate any other fish in the same 

 vessel. 



The nest-building habit of this fish is most curious. The spawnings 

 occur a number of times during the season, the floating nests being formed 

 of air bubbles coated with gelatinous matter expelled from the mouth of 

 the male. The eggs are deposited by the female, fecundated by the male, 

 carefully placed in the fairy nest and permitted to hatch, he guarding and 

 caring for them until the fry make their appearance. Then the nest is 

 destroyed and the young fishes are carefully tended until they are old 

 enough to care for themselves; the male assuming the whole duty and 

 keeping the female away from the young. When of sufficient age, the fry 

 should be fed with the same food as young goldfishes and later will thrive 

 on the prepared fish foods together with a frequent diet of earthworms or 

 small particles of raw meat and liver, though the fish prefers and thrives 

 best on living food. Daphnia, small worms, young snails, gnats, small 

 houseflies, moths and other insects are generally fed. 



THE STICKLEBACK 



This most interesting little fish inhabits streams which reach the ocean, 

 some forms frequenting brackish and salt water. It is one of the most 

 belligerent of freshwater fishes and may be bred in the aquarium, but should 



FIG. 3 6 — Four-spined Stickleback, Apeltes quadratus 



be isolated from other kinds. Its nest-building is very interesting and 

 varies considerably in the natural state. Some build upon the bottom of 



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