One of the main tricks Mother Nature has is
that she has LOTS of water to each fish.

Our garden ponds are overstocked compared
to Mother Nature's ponds and that's where
things start to get out of balance.

That also means that available food to the fish,
zooplankton, insect larvae, algae, worms, snails
and other tasties are available to Mother Nature's
fish and sustains them just fine.

kathy :-) www.blogfromthebog.com
this week ~ the rat-tail maggot!

And lets stress the words sustains them they have to go looking for
food, it doesn't drop out of the sky in handfuls at regular intervals.

And as far as water out, water in, as in water change outs I assume OP
might be referring to? You too could live in a typical room day in and day
out, but that air would get pretty stale if you weren't allow to open the
door and windows once in a while.

~ jan

~Power to the Porg, Flow On!~