The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1910-09-15
KEEPING THE FISHES COOL.
summer Comfort for the Specimens
in the Aquarium Tank.

Summer Comfort for the Specimens
IN the Aqunrian Tank.
Fishes in summer seek cool retreats, go
ing off shore to deep water or to shady
spots and cold spring holes in streams
Fishes in captivity must have cool water
brought TO them. declares the New York
Sun.
The trout and various other fresh water
fishes in tanks at the Aquarium would
coon die in water OF the temperature at
which IT flows from the city water main.
1 For their benefit there is installed at the
Aquarium refrigerating plant that keeps
| their tanks constantly supplied with wa
ter OF a temperature comfortable for
them in which they can exist The sur
plus water from these tanks is constantly
flowing off and the cooled water
is constantly flowing in. These are cir
culating tanks, but other means must be
adopted for keeping the water cooled in
balanced tanks
/ In a balanced tank commonly only so
much new water is put in from time 70 time
as may be required to make good that
lost by evaporation and the water is kept
sweet not by constant circulation, but
by the presence in the right Quantities
Of suitable vegetation. The carbonic
acid gas that the fishes in the tank give
of IN respiration is absorbed by the
vegetation and the vegetation gives off
oxygen, which the fishes require for their
existence Balanced salt water tanks
have been maintained for several months
and occasionally for years without a
total renewal Of the water, but occa-
sionally heroic measures are required.
As compared with circulating tanks the
balanced tanks are small. Most Of those
at the Aquarium are straight-slded round
glass jars somewhat larger than an
ordinary water bucket, and the stock
kept in them Is correspondingly small.
little fishes and crustaceans and sea
anemones and coral various smaller
forms Of marine life. These little fishes
and other creatures may suffer from ex-
cessive heat as much as the bigger fishes.
and when the water in their tank gets
too warm for them something must be
done TO make them comfortable.
When in the recent hot spell the tenn
perature OF the air here8oouts went up
above ninety degrees the water in the
balanced Jars rose TO eighty-six which
Is pretty near the limit Of what most Of
these little fishes can stand. so the at
, tendants set about making the water in
the balanced tanks cooler. They took
out half the water from each OF these
tanks and replaced it with water Of a
lower temperature.
/ r.
tanks are kept supplied. not with
, the polluted water OF the harbor, but
} with sweet water brought in from the
open sea outside Sandy Hook, and stored
in reservoir under Battery Park From
( this reservoir IT IS piped into the Aquari-
! UNI and 10 the tanks. 10 run thence
through a filter back 10 the reservoir.
the circulation thus maintained being
constant This water was now up 20
seventy-hye degrees. which would do
! nicely for the little fishes, but which
r would scarcely do TO mix with water at
! eighty-slx. the temperature Of the water
! remaining in the jars.
I Al that time the water in the harbor
here was OF temperature OF sixty
Z seven. so what they did was to take a
part reservoir water at seventy-ive and
e part harbor water at siXty-seyen. with
D which 10 FIJI up the jars and by the use
8 OF cooler waters in this combination
y they reduced the temperature Of the
D water in the jars from eighty-six e
. seventy-sx. Now they have got il down
e to seventy-four. and in the water OF this
e temperature the little fishes in balanced
I tanks are comfortable.