TROPICAL AQUARIUM FISHES 49 
for several generations and no fish varying from the desired type is 
allowed to breed, the percentage of young coming true can be kept 
very high. 
The beginner should get his first experience in breeding the more 
hardy varieties—the comet, for instance—but this stage passed he should 
select none but the best breeding fish out of known good stock. The 
best time to purchase new stock is in September and October, preference 
being given to the larger fish about seven months old. At this period 
the dealer-fancier is usually willing to sell off some of his larger old 
fish. These are more showy than the young, but should not be selected 
as breeders. In fact, none but the expert fancier who knows well what 
he is about should purchase any fish over one year old. 
The fish often show signs of breeding early in the year. As pre- 
viously stated the young males will start “driving” the females. If this 
is observed before March, the sexes should be separated, as early spawns 
are not to be desired, unless one has very special facilities. If the spawn- 
ing can be delayed until May, results will be more satisfactory. The 
reasons for this are that the harmful long cold spells are less likely to 
occur and that living food can be obtained with more certainty. Spawn- 
ing may be delayed by separating the sexes and by keeping the fish in 
cool water. 
As spawning time approaches the fish should be well fed on nourish- 
ing food. Finely chopped earthworms, carefully rinsed, are excellent. 
Live daphnia are even better. When the breeders have been selected 
they should be placed togther by themselves. If possible there should 
be three males to one female. This insures a higher percentage of 
fertilized eggs than if only one male is used. If the definite results of a 
certain cross are wanted then use only one male. A second female 
not spawning should never be present, as she will devour the spawn. 
Papier maché tubs are very nice for spawning in, but seasoned wood 
tubs or tanks will do. The aquarium may be used, or the spawning net 
shown on page 231. 
Should there be no spawn after the fish have been together several 
days, remove about a quarter of the water daily and replace by fresh. 
This is very stimulating. Some intimation of an approaching spawning 
may be had by the fact that the males occasionally “drive” the ripe 
female for several days before the spawning takes place. This usually 
increases in intensity the evening before, and when spawning is in full 
swing it develops into a wild chase punctuated by short periods of rest. 
So vigorous is the swimming at this time that fishes with large fin 
development generally have their fins torn and frayed. Males with 
shorter caudal fins (tails) are the more rapid swimmers and their fins 
