Evening star., 1934-12-11
THIS AND THAT
BY CHARLES E. TRACEWELL.

Aquarium water is something more
than just a medium for the fishes to
swim In.
It is q great deal more, as even
the beginner will find out.
He may get white water" or green
water; it may become crystal clear,
and yet fishes die in 1t; it may appear
terribly dirty. and yet the fishes live
happily therein.
He may wake some cold Winter
morning to find his charges dead, If
he has not taken seriously the ad-
monition of older hands that the
water in which tropical fishes are kept
should never 60 below a theoretical
10 degrees, at the lowest.
He may find his gay swimmers
gasping at the surface for air.
He may find fishes unaccountably
dying. even when he has followed all
the rules.
No, water is not just water. but a
complex medium, and for the pur-
poses of fish in the home aquarium
must be considered from four stand
points:
/. Temperature.
2. Oxygen content.
g. Chemical makeup, as to acidity
or alkalinity.
L. Mechanical condition.
The first Of these is by far the
simplest. 1t demands that gold fishes
be kept between so and IS degrees
for their best keeping, and that the
so-called tropical fishes have water
never below 70, with q preferred
range between IA and 78 degrees
They can stand it 10 degrees warm
er better than they can stand it 2
degrees lower.
The beginner who thinks this "all
bunk" as beginners so often do, will
have it impressed upon him some day
by Nature herself, so there is no need
to say more on the score.
The great lesson to learn, in fish
keeping. is that you can't keep them
the way you want to, but must keep
them the way they want to. That is
just one way. Of saying the keeper
must emulate natural conditions as
far as he can.
*k*
The matter of oxygen content is best
taken care of by giving the tanks
plenty Of strong light, preferably will
two hours Of sunshine per day, anC
limiting the number of fishes
Carbon dioMde is built up by the life
in the water. Some of it, but not all
is absorbed by the plants. which theo-
retically give of oxygen in return, but
which actually on cloudy days Absorb
oxygen.
There are other gases in water
sometimes such gas as methane. the
deadly one found in mines. These
gases collect on the lower levels of the
tank, and in Nature would be whipped
up by water currents.
Agitation of the water by the arti-
fetal introduction of air tends to breal
up these levels, and afford the case.
an opportunity to get to the surface
where they are absorbed into the air
The introduction of oxygen by thi.
means is problematical, but the rid
ding in the aquarium of the hurtful
gases works like magic, soothing the
breathing Of gasping inmates in q
comparatively short time.
X X
The chemical makeup of the water
is very complex, so much so that thou
sands of persons keep fishes without
every bothering their heads about it.
and often do very good job Of it.
Why bother about it, then? Be-
cause there is one plain danger to
every fish keeper, that lies in the too
sudden change of water in a tank
which has been running along nicely
for many months, perhaps. but in
which few fishes begin to die, for
no apparent cause.
The owner cleans out the tank, gives
1t new sand and plants and water,