THE AQUARIUM, APRIL, 1894. 



101 



such as are found in the true carp. 

 Thus again we have testimony to the 

 truth of the statement, that the male 

 goldfish can with certainty only be 

 distinguished when the tubercles make 

 their appearance during the spawning 

 season. 



In some species the males during the 

 breeding time are adorned with the 

 most beautiful colors, which give to 

 them a brilliancy not surpassed by any 

 other kind of fish. The dorsal fins in 

 all the species of minnows will be found 

 short. (See illustration of Banded 

 Dace. ) 



TRE BLACKHEAD. 



(PimejjJtales promelas. ) 



This is one of the most common 

 species of minnows and generally the 

 first object upon which our boys com- 

 mence their piscatorial studies. Under 

 the name of " nigger," they regard it as 

 the most j)recious specimen to be caught 

 for the preserve jar they carry with them 

 when on a minnow hunt, and which, 

 by-the-bye, is the a, b, c of an aquarium. 



The body of the male fish is some- 

 what stunted, cylindrical, of a dusky 

 color and covered with minute scales, 

 the dorsal fin showing a black spot. 



The head is almost globular, of a 

 black color, and in spring-time covered 

 with large tubercles ; the eyes and 

 mouth are very small. 



. The female is smaller, more delicate 

 in structure, compressed upon the 

 sides, lighter in color, with an indis- 

 tinct black lateral band. 



It attains a size of from two to three 

 inches. It is found "at home" all 

 over the entire Mississippi valley. 



This is one of the most common spe- 

 cies of minnows found in this country, 

 and being only a minnow, this little 

 fish has heretofore been very little 



noticed, more particularly in regard to 

 the method of its reproduction. We deem 

 it of sufficient importance to the scien- 

 tific public, fishculturists especially, to 

 make known the discoveries we made 

 in that direction while studying the fish. 



As their breeding season approaches 

 in the spring the head of the male 

 turns jet black, and numerous promi- 

 nent white and horny tubercles aj^pear 

 on the forehead, the entire body be- 

 coming blackish, darkest on the back, 

 leaving two lighter vertical bars of a 

 quarter of an inch in width on each 

 side, one of these right back of the 

 gills and the other immediately under' 

 the dorsal fin. The fins also undergo 

 changes in their coloring ; the dorsal, 

 pectoral and caudal fins become shaded 

 with black, and the dark spot in the 

 dorsal fin becomes larger and deep 

 black. In addition to this shading on 

 the fins the two smaller spines in front 

 of the largest one in the dorsal appear 

 inflamed and are spread in a position 

 pointing toward the head of the fish, 

 which at casual examination makes 

 this fin appear injured. The female 

 keeps its customary appearance with 

 perhaps the only difference that the 

 lateral band is more distinct than usual 

 and its belly larger. 



At this time the male selects a stand 

 under a floating, broad leaf, for instance 

 that of a i)ond-lily, and there induces 

 the females to come and deposit their 

 eggs. The eggs are deposited on the 

 lower side of this leaf, one at a time, 

 and being adhesive, remain there. To 

 accomplish this the fish twists its 

 body, and darting against the leaf de- 

 posits the egg in the moment of con- 

 tact. After one female has deposited 

 all her eggs, others are induced to do 

 the same on the same leaf ; thus leaves 

 may be found containing in large 



