126 
Aquatic Lite 
new Danio from Singapore). But when 
specimens were submitted to the great 
British Museum to receive a scientific 
name and the stamp of respectability, as 
used to be the custom with German 
aquarists before the war, it was pro- 
nounced a mere local variety of D. albo- 
lineatus. The “new Danio from Singa- 
pore” differed mainly in the imagination 
and seemed to me to be somewhat less 
brilliant than the type, a native of India. 
———— > ——— 
Mosquito Larvae for Fry 
H. E. FINCKH, Royal Zoological Society 
of New South Wales 
We are all aware that to successfully 
rear young fish much depends upon the 
food, and that it should be living food. 
Much has been said about propagating 
Daphnia, the favorite food, and, al- 
though I have tried almost every way 
suggested, I am only fairly successful in 
breeding quantities in tubs. I now feed 
principally on mosquito larve (Culex), 
finding this very desirable, easy to secure, 
and easy to handle. 
I once put a float or raft of eggs of 
Culex into a small jar to ascertain when 
they would hatch and, the following 
morning, was quite surprised at the quan- 
tity of minute larve (wrigglers) that had 
hatched in the interval. I emptied them 
into a tank containing quite small Xipho- 
phorus, and although | had just added a 
feed of Daphnia, the young fish ate the 
wrigglers in preference, until all which 
I could note had disappeared. This gave 
me the idea of using wrigglers for quite 
small fish. ‘To secure quantities of larve, 
I proceeded in this manner: 
First I established a tub, containing 
fifteen gallons of water, which I made 
stagnant with horse and pigeon manure, 
having both handy. When, after a week, 
it had cleared, I added a handful of 
Lemna (Duckweed), to afford the mos- 
quitoes a place upon which to rest while 
laying their eggs in the water. On the 
morning following I counted forty-seven 
egg-floats or rafts. These I spooned into 
two small glass jars containing two 
inches of water. Later, the weather be- 
coming warmer, I averaged quite a hun- 
dred such floats daily. When the eggs 
hatch I merely pour the contents of the 
jar into an aquarium. 
Now a float is said to contain from 
200 to 300 eggs and, if we say 100 eggs 
to be conservative, and I collect 100 floats 
daily, it means that my fish eat 10,000 a 
day. 
It is far preferable to breed the pest 
in the manner outlined than to permit 
the eggs to hatch in the tub, collecting the 
wrigglers in a net, as it is inevitable that 
some will manage to complete the meta- 
morphosis and escape to plague you and 
your neighbors. Then again, if you re- 
quire them larger, place eggs in a large 
jar and feed for a few days or until the 
desired size is reached. 
I certainly find my fishes doing well on 
larve, and the method is less trouble- 
some than collecting and sieving Daphnia, 
not to mention the lessened likelihood of 
introducing organisms that may be detri- 
mental to the fish. 
I have reared young fishes quite suc- 
cessfully on artificial foods, but living 
food is better, not only because it is what 
nature provides, but because it must be 
sought by the fishes, and the exercise 
which is thereby taken cannot but be 
beneficial. 
(The elongate eggs of the mosquito 
are laid vertically, side by side, in raft- 
like masses, which vary from 1g to 4 
inch in diameter, though capillary 
attraction may draw several together, 
thus making a seemingly larger 
individual float. Light in color at first, 
they become darker and soot-like as in- 
cubation proceeds. The larve emerge in 
five or six days.—Editor.) 
