t 



The Aquarium 



Volume II 



V 



JUNE, 1913 



Number 3 



Tetragonopterus rubropictus. 



O. T. HEEDE, Brooklyn, N. Y. 



THIS fish is also called "The Blood- 

 fin". It is a very beautiful, spawn- 

 ing fish adapted to the aquarium. Its 

 habitat is Argentina and the Southeast 

 of South America. These fishes, although 

 imported to Europe several years ago, 

 are seldom seen in this country, but 

 will, when known, be much favored in- 

 habitants of our aquaria on account of 

 their great beau- 

 ty, alertness and 

 steady health in 

 captivity. They 

 are about two 

 inches in length, 

 olive green 

 above, and a 

 silvery gray 

 stripe runs from 

 head to tail on 

 each side of their 

 body. The ab- 

 domen is silvery. 

 In bright sun or 

 artificial light 

 they look steel- 

 blue, violet and 

 green, — in other 

 words, like a newly caught herring — 

 but with all their fins, (except the 

 pectoral and the very small adipose 

 fin), and their tail colored blood-red 

 with a silvery outer lining; the bright 

 red color is more intense near the body. 

 The sexes look alike in size, shape and 

 color except just at breeding time, when 

 the female has a heavier abdomen than 



TETRAGONOPTERUS RUBROPICTUS 



DniwinLC liy E. S VouNO. 



the male. At other times the sex can 

 be determined by lifting them from the 

 aquarium in a very fine meshed net and 

 turning them down into the water. The 

 female will fall down first; the reason 

 for this is that the male has some minute 

 appendages — not visible to the naked 

 eye — which easily catch in the fabric 

 of the net. This is an infallible way 

 to detect the sex of the fishes. The 

 temperature of the water in the tank 

 where Tetra- 

 gono pt erus is 

 kept should be 

 from 60<^ to 70" 

 Fahrenheit; in 

 breeding time 

 from 15^ to 80" , 

 and equally 

 warm for young, 

 newly hatched 

 fishes. 



To keep the 

 fishes healthy, 

 the water in the 

 tank should be 

 changed once in 

 a while with 

 fresh water of 

 the same tem- 

 perature, and especially to get the fishes 

 to spawn, fresh water with a very little 

 salt added is necessary. 



The eggs are white. They are scattered 

 by the female all over the tank between 

 the plants, and sink to the bottom. 

 Some 200 to 500 eggs are produced at 

 each spawning, and they hatch in about 

 twenty-four hours. The parent fishes. 



Copyright. 1913, by W. A. Poys 



