ZOOLOGICAL 
POLISHING cca 
Published by the New York Zoologr 
SOC 
sont Instity, 
/ 
ly 
Ra 
UL 25 1921 
NV y® 
tae 
Votume XXIV 
AMON EE 
1921 NuMBER 4 
TROPICAL 
TOY FISHES* 
By Ipa M. Meiien 
ECAUSE of their handsome colors and 
great fecundity, various species of minute 
tropical fishes have become popular for the 
home aquarium. Some of these little fishes will 
live in water of the temperature of the living 
room, provided the heat is maintained steadily 
throughout the colder seasons, and they do 
especially well when the aquarium is protected 
by a sheet of glass laid upon the top. This is 
always a desirable provision, as most fishes are 
apt to jump out. 
For the special heating of a tank in the 
home where a proper degree of warmth is un- 
certain, aquaria are manufactured with a metal 
sleeve built in, into which a tubular incandescent 
lamp may be inserted; but if one does not wish 
to purchase a special tank for his tropical 
fishes, he can provide himself with a water-tight 
brass sleeve, nickel plated, made for the same 
kind of bulb, and place the whole apparatus in 
the water by suspending it over the side of the 
aquarium whenever extra heat is necessary. The 
suspension of an incandescent lamp in the 
aquarium is also effective, care being necessary 
to prevent any metal parts from striking the 
water. 
Nearly all tropical toy fishes will breed in a 
temperature of from 68 degrees to 75 degrees, 
and they breed during the better part of the 
year. In live-bearing species the female re- 
mains fertile for some months after giving birth 
to one family, producing more young from time 
to time, though there is no male in the aquarium 
with her. 
Like goldfishes, they require a well-balanced 
tank, with plenty of plant life and an hour or 
*Indebtedness is acknowledged to Mr. Richard 
Dorn and Dr. E. Bade for their kind reviewing of 
the chapter on Tropical Fishes. 
two of sunshine daily; but must not be given 
cold water from the faucet. Water, to replace 
evaporation and siphoning, should stand until 
of the temperature of the room. Siphoned 
water may be used again by straining back 
through cheese-cloth. 
Most tropical toy fishes are destructive to 
snails, eating off their tentacles down to the eyes 
and killing them, and tadpoles are too large 
and boisterous to be placed with them. Most 
species will forage for such food as falls to 
the bottom, but for their complete well-being 
siphoning must be resorted to for clearing the 
tank of uneaten food and debris. 
Sagittaria is the best of rooted plants for 
oxygenation, but for live-bearing species the 
tank should also be stocked with bushy plants 
of the order of Myriophyllum and Cabomba for 
the shelter of the young against their cannibal- 
istic parents. For this purpose nothing is 
superior to floating Riccia, masses of which, 
hanging several inches down from the surface, 
form a dense aquatic jungle in which the fry are 
sate. 
Those that lay eggs and do not care for the 
young will eat their spawn the same as gold- 
fishes do; but non-adhesive eggs may be saved 
if they fall between large pebbles or among the 
roots of plants, and adhesive eggs may be saved 
by removing them with the plants to which they 
are attached. Various sieve-like devices have 
been invented for permitting non-adhesive egrs 
to fall through and rest on the bottom, where 
the young may develop in security. 
It is a wonderful experience to start with a 
pair of fishes an inch long and some day dis- 
cover a dozen babies in the tank three-eighths 
of an inch long and looking like nothing but 
two big eyes attached to a wee gray streak 
[ 81] 
