The Portland daily press., 1893-10-26

haunts. The water is kept aerated by
means of a jet of air projected into each
tank by powerful force pump. This is
found to be more satisfactory plan in
most instances than supplying fresh
water A few of the tanks, on the other
hand, are what are termed balanced"
aquaria; that is to say, the vegetable
life and animal life in them keep each
other going the plants yielding oxygen
and feeding the fishes, and the latter
giving Off carbonic acid to feed the
plants The only other element required
is sunlight and plenty of it. But the
fishes in confinement have to he treated
very gingerly. If brook trout, for ex-
ample, are allowed to gocge themselves
freely with meat for onlya few days
their eyes burst
One of the aquaria is filled with grow
ing salt water plants from the Chesa-
peake. They form quite marine gar
den, beautiful to the eye and interesting
to the student of nature. Another tank
OF fresh water holds lot of young cat
hsh about four inches long. They were
matched and reared at the building OF
the fish commission, whiskers and all
Ihe larger fishes in oJher receptacles are
eyed enviously by visiting small boys,
who, accustomed to angle for much
lesser fry in the Potomac, are sure that it
would be great sport to drop line for
"a I'LL VI UuuuOS lnUO uuO uol 1u.
Fisheries at the Fair.
The fish commission has been quite sur
prised at the success of its marine
aquaria at the Worlds Fair in Chicago,
viewed merely as biological venture.
OF course no doubt was felt that they
would do we'll, but they have so far ex-
ceedcd expectations that the salt water
fishes have actually done far better than
the fresh water forms. Whereas among
the latter there has been considerable
mortality, as was expected, scarcely a
death in months has occurred in the
marine tanks. When it is considered
that the fresh water aquara have been
supplied with that element in an I'M
| limited stream from the Atlantic ocean
in vessels transported on fiat cars, the
result certainly seems astonishing.
The presence of parasites in the fresh
water has been chiefly accountable for
the mortality among the fishes native
to that element. Such destructive organ
isms appear to be far less numerous in
"the briny,n and do not do such deadly
work at the expense of poor finny vic
Tins. The accepted treatment for fresh
water fishes that are infested with para
few days AT the Matching stations
for trout and salmon the young fry are
regularly asalted," as the term is, once
a week. The current of water running
through the troughs in which they are
kept is cut off for a while, and into each
trough, holding twenty or thirty gall
Ions, are poured two gallons of saturat-
ed solution of salt and water.
At the same time the sides and bottom
of the troughs are scrubbed with brushes
to remove thesaccunulated slime. This
process gets rid of much parasitic life,
and the salt water serves incidentally as
tonic for the little fishes. Salt, of
course, is an excellent disinfectant.
Marine parasites generally cannot LIVER
fresh water. When a ship from the
ocean goes up a river and stays for
awhile, the barnacles and ship worms on
her bottom get sick, die and fall out of
their shells finally. On this account such
vessel will often be found surrounded
by shoals of fish in stream, such as
perch and crappies. feeding on the dis
abled mollusks, and by scooping with a
hand net beneath the hull the energetic
sportsman can make a fine haul some
times