146 FEESH-WATBR AQUAEIA. 



instead of backing out by tte way she entered, makes for herself 

 a door in the opposite side of the nest. The eggs just deposited, 

 only a few in number, are of a yeUowish-pink colour, and 

 about the size of a German rape-seed. A slight current of 

 water now sets in between the two doors of the nest, which is 

 of great benefit to the ova inside. The fickle little male, after 

 entering the nest himseM, at once discards his bride, and in a 

 few hours sets out to find and win another. In this way the 

 nest is visited by several female Sticklebacks until the necessary 

 number of eggs has been laid. The male now becomes more 

 vigilant than ever, and jealously guards the nest and spawn, 

 furiously attacking any other inhabitant of the tank that may 

 venture too near. The little fish spends the greater portion 

 of his time in re-arranging the eggs, and in fanning them with 

 his fins as he balances himseM obliquely before a door of the 

 nest. After a little while the young fish may be seen moving 

 slightly within the eggs — that is, supposing they are closely 

 examined — and in about a month (according to the temperature 

 of the water) from the time they are deposited, the fry are 

 hatched. At first they are so small and transparent that it is 

 not an easy matter to see them. With the appearance of his 

 offspring, the male Stickleback's cares seem to increase, and 

 though he worked so hard during the incubation of the ova, 

 he has to work much harder now ; for not only has he to guard 

 his little ones from the attacks of his discarded wives and other 

 fish, but he has to carefully confine them entirely to the nest. 

 Should they, however, elude his vigilance for a moment, and 

 escape from the nursery, they are either quickly driven back 

 or are seized in their protector's mouth and forcibly returned. 

 Old Sticklebacks are exceedingly fond of Stickleback fry, and 

 should the father of the little ones die or be taken away, every 

 other Stickleback in the aquarium will immediately act the 

 part of cannibals, and much enjoy the acting. 



The eggs of Sticklebacks are very large in proportion to 

 the size of the fish which lay them; and in comparison with 

 the quantities of eggs deposited by many other fish they are 

 very few in number. As the eggs are so large, so plainly 

 seen, and such tempting food to fish generally and even to 



