THE 



AQUARIUM 



11 



Xiphophorus Helleri. 



JAMES H. OLSHAN, Chicago, 111. 



/^\NE of the most interesting members 

 ^-^ of the Viviparae is Xiphophorus 

 Helleri, commonly called the sabertail, 

 or just Helleri, from Mexico. It is said 

 to be not uncommon in the streams. 



Although it can attain a length of four 

 inches, it seldom reaches this in aquaria. 

 The body of the fish is somewhat com- 

 pressed, except the abdomen, which is a 

 little swollen. The upper part of the 

 body is olive green, while the abdomen 

 and under parts are silver white. A red 

 serrated line extends from back of the 

 eye to the tail. A black stripe from 



female as they cavort about in the 

 aquarium. The female differs from the 

 male in the absence of the saber and in 

 being of a duller coloration. The saber- 

 tail develops as the fish matures. It 

 has been observed that those fish which 

 develop it while still small do not 

 become as large as those which make 

 body-growth first and acquire the ap- 

 pendage later. 



The specimens that I have had the 

 opportunity to study were of a very 

 cautious yet inquisitive nature. Upon 

 seeing an intruding object in the aquari- 

 um one would stop as if hestitating, 

 and, watching the object, would cau- 



<S>**^ 



SABERTAIL. Xiphophorus Helleri 



Courtesy of Chicago Fish Fanciers Club 



the eye to the mouth gives the fish a 

 masked appearance. 



The mouth of the sabertail is peculiar. 

 The lower jaw projects forward and 

 upward to the nose or snout. The 

 "chin" appearing to be on a level with 

 the top of the head. The mouth is thus 

 well-shaped to take particles of food 

 from the surface of the water. 



The most interesting characteristic of 

 this Xiphophorus, however, is the saber- 

 tail of the male. This tail is an elonga- 

 tion of the lower rays of the caudal fin 

 and is about one and three-quarters 

 inches in length. It is in the form of 

 a curved sword or saber and is yellow 

 heavily bordered with black. This 

 peculiar appendage is vised in playful 

 antics wherein the male strokes the 



tiously approach it, only to dash away 

 immediately. But curiosity would soon 

 overtake it, and again it would turn 

 around to watch the object closely. 



Xiphophorus Helleri is a hardy in- 

 habitant of the aquarium and can be 

 easily kept, providing no misfortunes 

 happen. It must have an average tem- 

 perature of 72 degrees, Fahrenheit, 

 although it can live in water as low as 

 60 degrees. If conditions are favorable, 

 it will breed every four to six weeks. 

 After fertilization has taken place, the 

 male should be separated from the 

 female as he then becomes troublesome. 

 The young, varying in number from 

 eie;ht to a hundred, are born alive, and 

 should be fed upon Daphnia and Cyclops 

 until about three centimeters long, and 



