Silly Question?

Jay Rao jprao at
Wed Apr 27 05:13:17 EST 1994

I am not a student of Biology or Chemistry, so I had a question for
these students.
When we keep fishes in a Water Tank, why do we need air pump?  If
we don't have air pump, why is there a need to change the water
I thought water H2O contains O2, which can be extracted by the
fishes.  Also, I thought Water is capable of absorbing O2 from air.
If that is so, then there is no need to change water in the tank
Another question is How do salt or clear water fishes manage to
breath, if there is no recycling of water?
These questions most probably silly.  But I do not know the
If someone can answer these questions, it will be helpful.
Jay Rao  (e-mail: jprao at

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