ZOOLOGICAL SOCIETY BULLETIN 57 
leaves along the edges of the old ones, the new 
ones breaking away and forming independent 
plants. One should therefore place only one 
plant of this kind in the aquarium to begin, for 
in a few months in a good light it will spread 
over the entire surface. 
Pondweed, Sagittaria and other rooted plants 
reproduce rapidly in a bright light, sending out 
green rootlets over the surface of the gravel or 
mud, which soon develop roots and leaves and 
form new plants. 
Plants should be disinfected before intro- 
duction to the aquarium, to avoid trouble from 
leeches, aquatic insect larvae, fungus, or other 
destructive agents. For this purpose a weak 
solution of phenol sodique or of permanganate 
of potassium may be used, or a tablet of bi- 
chloride of mercury to a gallon of water. All 
traces of the disinfectant should be washed off 
before placing the plants in the aquarium. 
Goldfishes like to clean their gills with fine 
sand, and a place where they can always find 
clean bird gravel will help keep them well and 
happy. 
In setting up an aquarium it will be noticed 
that water drawn fresh from the faucet pro- 
duces oxygen bubbles. It is unwise to allow 
these bubbles to collect on fishes, and they 
should be carefully removed from plants and 
glass with a slender stick before the fishes are 
introduced. 
An aquarium thus begun need not be reset 
oftener than once in six months, half an hour’s 
attention each week being sufficient. The pro- 
gram for this half hour should be about as 
follows: 
With a glass siphon, procurable at any bird 
store, siphon off the sediment and refuse. While 
the water is lowered, clean the inside of the jar 
with a bit of felt or cloth fastened about the 
end of a stick. If algae has formed on the glass 
it can be scraped off with a bit of cuttlefish, but 
if one has snails they can be afforded a brows- 
ing ground by leaving untouched a space of a 
couple of inches in breadth from top to bottom 
of the aquarium, behind the plants, where algae 
may grow undisturbed. In replacing water 
siphoned off, use water that has been standing 
until of the temperature of the room. Some 
aquarists strain back the same water that has 
been withdrawn. 
For replacing water in an aquarium of three 
gallons’ capacity or over, nothing is superior 
to a small watering can, which disperses it 
evenly over the surface, like rain. Another ex- 
cellent method is to hold a tumbler over the 
aquarium in one hand, allowing it to rest just 
below the surface of the water, and pour the 
new water into the tumbler from a_ pitcher 
held in the other hand. If water is poured di- 
rectly into the aquarium, its violent entry will 
uproot the plants and be likely to necessitate 
entire resetting. 
To replace the salts and lime of the natural 
pond, salt and plaster of paris or cuttlefish are 
generally employed. A pinch of table salt, sea 
salt or epsom salt, with a bit of ground cuttle- 
fish, are used by some aquarists; or a mixture 
of one or two kinds of salt with an equal amount 
of plaster of paris. Salt does not evaporate, 
but plaster of paris does, and more of it can 
be added from time to time. 
A still-water aquarium can be a success only 
when a perfect balance is secured between its 
plant and animal life. It is hardly possible to 
have too many plants, but too many fishes in a 
jar are like too many people in a room. They 
soon use up the oxygen given off by the plants, 
the plants cannot take up all the carbon dioxid 
thrown off by such a superabundance of fishes, 
with the result that the animals die off until a 
proper balance is established. 
Goldfishes habitually come to the surface and 
blow bubbles or suck in air, and this need oc- 
casion no alarm except when they suck audibly. 
When they can be heard across a room—and a 
small fantail can “cluck” loud enough to be 
heard twenty feet away—it is a plain call for 
oxygen. 
A fish’s distress signals should be heeded by 
opening a window and allowing a draft to play 
across the surface of the water, also by siphon- 
ing off a quart or two—in this instance a small 
rubber tube is the quickest way—and replacing 
with cold water from the faucet. 
Like the bowl of water on the old-fashioned 
“parlor stove,’ the aquarium absorbs the 
poisonous gases of the room, and does this work 
best in a warm room in winter, when many 
homes are improperly ventilated and rooms are 
allowed to become overheated. The proper 
temperature for a normal human being is 68 
degrees, and if this is maintained the fishes do 
not suffer. 
One of our frequent inquiries at the Aquarium 
is “ Does tobacco smoke injure fishes?” 
Chemists’ experiments show that in addition to 
marsh gas, carbon dioxid and other gases, an 
ounce of burning tobacco gives off three pints 
of carbon monoxid gas—all poisonous gases, 
soluble in water. The water absorbs these 
gases so slowly, however, that the general be- 
lief is that smoking in a room with open win- 
dows that allow a free circulation of air over 
