196 Animal Life 
Girardinus unitotatus and 
Gambusia Holbrookt, which 
is distinguished for its ele- 
eance and small size. The 
Girardini also breed in the 
aquarium. 
Of native fish, both 
varieties of the stickleback, 
and the carp, are profitable 
and interesting inhabitants 
of the aquarium. Both are 
comparatively easy to rear, 
and the student who has 
NZ) ~=6already bred with success 
BOW-FIN. the paradise fish, which is 
very easily brought up in confinement, will find great pleasure in the rearing of stickleback 
and carp. The former build a nest of vegetable matter for their eggs, whilst the carp 
lay their eggs in the 
crevices of shells of 
the fresh-water mus- 
sel, which the young 
afterwards quit, to 
exhibit themselves as 
quite large fish in 
the aquarium. 
Whilst the fish 
so far mentioned 
may be kept during 
the winter in an 
unheated aquarium, 
provided it is placed 
in a room of even 
temperature, it is 
necessary for the 
keeping of tropical fish to provide the tank with a heating appliance. The illustration 
on page 194 shows a simple form of aquarium with heating apparatus. In this, half of 
one pane of glass in the 
smaller side of the receptacle 
is replaced by a sheet of 
zinc, which forms one side 
of a closed water-tight zine 
box, from which a _ broad 
slanting tube leads to the 
surface of the water. The 
heating is accomplished by 
means of the small flame of 
a spirit-lamp. Such a tank 
is suitable for the Indian 
fighting fish (one of the 
most brilliantly coloured fish 
hitherto imported), the 
NORTH AMERICAN GOLDFISH. 
BRAZILIAN FISH. 
