28 Aquatte Lite 
is not possible for one to distinguish be- 
tween suspended animation and absolute 
lifelessness, yet every fish saved encour- 
ages to further efforts, and the labor en- 
volved is slight. 
Breeding Danio Rerio 
JACOB MERGET 
The little Danio rerio from the East 
Indies, is, in the opinion of the writer, 
one of the most attractive of our aquar- 
ium fishes. Further, it is not a difficult 
Lower, Male 
Danio rerio 
Upper, Female 
species to propagate, and is therefore a 
desirable species for the beginner, most 
of whom look for one of the egg-laying 
class after having successfully bred some 
of the live-bearing kinds. There is some- 
thing sprightly about this fish that com- 
pels attention, not to mention its inces- 
sant activity ; it is never still a moment. 
The back is olive-green, which merges 
into indigo blue on the sides to the yel- 
lowish belly. Golden stripes run length- 
wise along the sides from the gill-covers 
to the tail, the anal fin being likewise 
striped. The pectoral and dorsal fins are 
greenish yellow, the latter with a dark 
margin edged with yellowish white. The 
barbels or “whiskers” are so slender and 
transparent that they can seldom be dis- 
cerned. The males are slender; the fe- 
males deep through the abdomen, espe- 
cially when gravid. 
My breeding tank measures 20 by 12 
inches, and contains a nice growth of 
Vallisneria. The sunny corner nearest 
the window, where the plants are thicic- 
est, 1s the spot the fish chose for spawn- 
ing. Here “with malice aforethought” I 
have an egg-trap consisting of a number 
of pebbles, one to two inches in diam- 
eter, placed among the plants. Directly 
above floats a clump of Bladderwort 
(Utricularia) ; this also serves a purpose. 
When spawning is imminent the males 
swim along the bottom towards or in 
front of the female, color intensified and 
with whiskers distended ; the female wii. 
be round and plump, so much so at times 
that swimming in the usual manner 
seems difficult. During the operation the 
male chases or drives the female, each 
dash usually ending in the clump of Utri- 
cularia. Here the eggs are expelled and 
fertilized, dropping into the trap below 
before the fishes are able to catch and 
devour them, which they will do if the 
water depth is too great. If more than 
six inches they will be able to capture 
them before they reach the bottom. 
With intervals of a few minutes the 
spawning proceeds until all the eggs have 
been expelled. 
The pebbles are now lifted and the 
eggs removed with a dip-tube to a shal- 
low dish, which is placed in a warm, 
sunny place for incubation. Hatching 
takes place forty hours to four days 
later, being dependent upon the tempera- 
ture, which should be, 1f possible, about 
75 degrees or more. The fry require an 
abundance of Infusoria, which should 
be fed several times daily until they are 
large enough to eat tiny Daphne and 
Cyclops. 
A supply of Infusoria can be produced 
by placing a pinch of dried aquarium 
plants in a quart jar. A number of such 
jars should be prepared a week or two 
before the fry are expected. A pinch of 
the dried plant will be sufficient for each 
jar; too much will decompose with a 
bad odor. To feed the fry it is merely 
necessary to pour a cupful of the water 
from a jar into the rearing tank. 
