Evening star., 1934-08-04

IL all purchasers. especially beginners,
would observe this rule. either in its
ordinary or it's extended form
When the fish hobbyist comes 10
tropical fishes. he Ii up against an
entirely different proposition. These
fellows normally live In warmer wat
ers. and the warmer the water the
less oxygen 1t holds Therefore they
become used 10 water not holding as
much oxygen as the cooler water IN
which goldfish live in nature.
This means that the tropical fishes
may be crowded in a home tank.
without undue harm TO them. There
can be little question. however. that
this fact has been grossly abused.
Almost every home aquarium one sees
Is overerowded. The fishes live. and
even breed but they do not live as
we'll. and the resulting offspring are
weaker than they would have been
In tanks uncrowced.
The time win come when amateur
fish culturists everywhere viii accord
their small troplcals as much room
as gold fishes.
Until that happy day-particularly
happy for the fishes-home tanks will
be crowded, and. no matter how fine
they seem, with clear, sweet water,
and lively inmates, the latter will be
living constantly just on the danger
line.
II Is because the fishes do thus live
right on the border between q healthy
tank and an unhealthy one that
many OF them from time to time de-
velop green water"
The remedy. then, appears to be
to cut down on the number OF fishes
in the tank which goes green, to pat
in more plants. to cut down largely
ON the amount OF food put in. and to
cut of the light which strikes the
tank.
Good tanks are placed in plenty
OF light. The free-living forms OF
Algae thrive IN such light. The old
theory was to shade the tank, espe-
elally the back side, usually next the
window. This was supposed 10 kill
the minute plants. gradually clearing
up the tank. And sometimes, Ger
tainly, it does work out that way.
but not always, as every aquarist
knows to his sorrow. For no matter
how good for the fishes the green
water may be, 1t spoilS the appear
ance OF tank, and dims the bright
ness Of the little swimmers. Hence
1t must be got rid Of. even II one must
go to the extreme of making the tank
completely over at last
Often it will be found that q COM
bination OF measures, as suggested
above, will remove the green from
the water completely, but not over
night One should not become i'm
patient, but allow at least two weeks
for this change to take place. II it
does not occur in that time, one
might as well empty the tank, wash
it thoroughly with salt water, rinse,
wash the old plants as thoroughly
as possible, fill the tank anew, and
put the fishes back. Then shade the
back for at least q week. in the
meantime feeding the fishes very
sparingly, and only with such foods
as offer a minimum Of fine residue
on the water. Even when such par
ticles float. they in time dissolve,
making the very finest nourishment
for free-living algae forms. Another
good step is to place clean sheet of
absorbent paper on the surface of the
water after feeding III order to take
up with it as much of the finer par
ticles as possible. Small tadpoles, no
doubt, are helpful. too. We cleared
up 10-gallon tank last Winter by
these means, and 1t has remained as
clear as crystal since. A 4-gallOn
tank this Summer has gone green,
and stays green. refusing to clear up.
The only essential missing is the tad
pole, but whether it spells the diff
ference between success and failure
we are not at this time able to say
One tadpole to every gallons is about
right