The Inhabitants of the Aquarium 203 



stems holding it, by an extra quantity of 

 gravel, which he carries to the spot in his 

 mouth. In about two days the little glob- 

 ular nest is finished, the openings, serving 

 for entrance and exit and facing each other, 

 have been made and now begins the spawn- 

 ing process. 



The male by pushing and playing coaxes 

 the female fish into the nest where the eggs 

 are deposited; this done the male fertilizes 

 the spawn and keeps a careful and indefat- 

 igable watch over the nest and its precious 

 contents. If one desires to keep the female 

 alive, she should now be removed from the 

 aquarium; otherwise the male will certainly 

 kill her. Nothing is allowed to come near 

 the nest and even much stronger and larger 

 fish than the Stickleback are attacked with 

 blind fury and driven away in the most 

 persistent manner. To secure fresh water 

 and a sufficient amount of oxygen for the 

 eggs the male will take up a position in 

 front of one of the openings and, by a rapid 



