
488 FRESH-WATER AQUARIUM. 
fishes to be selected for the aquarium ; collecting together in 
schools, tame, hardy and lively, they have qualities which 
few aquarial specimens possess. The stickleback ( Gasteros- 
feus) of which there are several varieties, is hardly a fish 
for the general collection ; although of exquisite form, it is 
so fierce, especially in the breeding season, that’ it inces- 
santly attacks the other fishes in the aquarium, and in a 
short time deprives them of more or less of their tails, mak- 
ing the unfortunate victims literally top-heavy, swimming 
with their tails, or rather what were once tails, much higher 
than their heads. 
Sticklebacks should have a tank devoted exclusively to 
them and this especially if we wish them to build a nest, 
one of their peculiar accomplishments. Early in the 
spring the sticklebacks may be found in great numbers in - 
the small ditehes which drain the salt-water marshes. The 
male is easily distinguished from the female by its deep red 
color around the gills and its blue eyes, while the female has 
only the silvery scales. A pair taken at random usually 
live peaceably together; if it is in the right season they 
will soon look about for materials for a nest, taking bits of 
water-plants and even coming to the surface for small pieces 
_of straw and sticks; with such materials they build a 
round nest about as large as a small English walnut, hollow 
in the centre and eed two holes large enough to admit 
the fish on either side; the nest is built upon the branches 
of some of the water-plants. While the female is laying 
the eggs the male acts as guard, fiercely driving away any- 
thing coming within a certain radius of the nest. When 
the eges are Li they resemble small globules of wet sago 
more than anything else. The female will be seen to fan 
these eges quite often with her fins; this is probably to give 
them fich water and to prevent any sediment from collect- 
ing upon them. After a fortnight or so, instead of eggs, We 
see in different parts of the tank what at first look most like 
«Very Minute gold spangles as large as the head of a small 

