THE PROPAGATION OF THE GOLDFISH 



means of discriminating the sexes is the appearance of the fishes near the 

 anal region. The female shows a slight protuberance above the anus, the 



protrusion of the oviduct; while the male has a 

 depression in this region as though a tiny piece of 

 the flesh had been pinched out with the nails of the 

 finger and thumb, Fig. 56. These latter differences 



FIG. 56 Difference at anal • ii ii • 



region of female and male Gold- ^rC nOtlCablC at all timCS. 

 fishes, for determining the sex. 



The conduct of the male in pursuit of the female shows unmistakable 

 evidence of courtship; swimming beside and around her, rubbing her sides 

 and pressing on the ovaries with the head and tubercles, aiding her in 

 depositing the spawn, often fairly forcing her on the spawning bed. 



At this season the enlarged ovaries of the female give to her a de- 

 cidely fuller and more distended appearance and also aid in the discrimina- 

 tion of the sexes, though the otherwise general conformation of body and 

 fin may be alike. It is generally recognized, however, that the males of 

 finely bred goldfishes incline to longer bodies than the females. 



The female deposits the spawn, Fig. 54, on the leaves and roots of aquatic 

 plants, its mucilaginous covering causing an adhesion thereto, where it is 

 covered and fecundated with spermatic corpuscles by the male. To the 

 breeder the preferable plants for spawning are Myriophyllum, introduced 

 in loose bunches, and the Water Hyacinth whose finely spiked floating 

 roots are well adapted to this purpose. Previous examination is advisable 

 that they harbor no snails, insects, larvas, or other enemies that may de- 

 vour the spawn or injure the fry, if introduced with them into the hatch- 

 ing dishes. Preferably the plants should be placed in water for some time 

 so that the larvae will hatch and then thoroughly cleaned in a weak solution 

 of Phenol-sodique before use for spawning. 



When the fry has reached the stage of development that the yolksac 

 entirely disappears, feeding is necessary and this consists of the tiny water 

 plants known as Algae, and of minute aquatic animalculae which abound in 

 quiet pools and still water, entomostraca of the genera Daphnia, Poly- 

 phema, Ceriodaphnia, Sida, Cyclops and Cyprus; also mosquito larvae and 

 those of harmless insects, of which more will be stated hereafter. Great 

 care must be taken in the selection of this food that injurious insect spawn 

 and larvae, or the protozoa and fungi which produce diseases, and parasites 

 are not introduced with it into the rearing tanks. This will also be treated 

 of elsewhere. 



If the bi-eeding is undertaken in a small way, a fine net of cheese 

 cloth and ajar containing a little pond soil and a water plant are required 



91 



