146 
Aquatic Rite 
all times, and the food requirements met, 
then success may be expected. 
The fantail practically demands a diet 
of live food, for on such it depends in 
its haunts. During the summer months 
give it mosquito larve—it will exhibit 
unexpected dexterity in catching them— 
vary with small pond snails, which may 
be had in abundance, and with caddis 
worms and daphne, or with the many 
small larvee from a neighboring creek or 
pond. Winter will bring to an end the 
supply of some of these foods, but it will 
be possible to get daphne and Corethra 
larva, even though ice must be broken 
to reach them; a supply of snails may be 
kept in other tanks. Though we have not 
tried them it will probably relish “enchy- 
tre” worms. High temperature will be 
the main summer difficulty, and lack of 
living food that of winter, but both can 
be overcome. The fan-tail will eat the 
dry foods, but they should be used spar- 
ingly, and only in a “pinch,” in which 
case care must be exercised to remove 
unconsumed particles before the develop- 
ment of fungi, and to otherwise keep the 
bottom clean by the frequent use of the 
dip-tube. Changing a portion of the 
water occasionally will be advantageous. 
Hydra: The Pest 
HARRY COLQUHOUN 
The pest of pests, in the opinion of the 
aquarist, is the freshwater polyp. Re- 
gardless of care it may be introduced 
into the aquarium containing one’s most 
valued fry, and woe betide them! The 
Hydra is a relative of small marine jelly- 
fishes, the Portuguese Man-of-war and 
some corals, and like them is abundantly 
provided with nettling organs with which 
to overcome its prey. Even the young 
of live-bearing fishes will succumb to 
the third attack; fry of egg-laying fishes 
end their career with one. 
Hydra is tubular in form, and attached 
at one end to some object; at the free end 
is a hole, the mouth, which is surrounded 
by a number of tentacles, usually six or 
eight. A large specimen will have a body 
three-quarters of an inch long, with ten- 
tacles of equal length. From the tenta- 
cles are discharged the minute stinging 
threads, which paralyze and cause the 
death of any minute animal coming in 
contact with them. The body and tenta- 
cles are capable of great contraction, and 
when prey has been captured, the animal 
Hydra Attached to Duckweed Drawn by Frank J. Myers 
appears as a small lump, with a coronet 
of very short tentacles. 
In the aquarium the Hydra reproduces 
freely (alas! too freely) by budding, a 
small excrescence appearing on the side 
of a mature individual, which gradually 
develops into a perfect organism. ‘This 
young Hydra may remain attached until 
nearly as large as the parent, and may 
even in its turn produce buds, but all will 
eventually become detached. 
The other method of reproduction is by 
eggs, which protrude as small globules 
from the lower portion of the animal. 
After fertiliziation these develop direct 
into new Hydra. 
Many methods have been suggested to 
eliminate Hydra from an infested aqua- 
rium. The most satisfactory is to remove 
all the fishes and snails, and syphon out 
the water, then refilling to the top with 
new water at a temperature of 104 deg. 
This effectually kills the pest. Replace 
this with water of average temperature 
before returning the fishes. 
