On Mon, 22 Aug 2005 18:16:59 +0100, Conrad wrote:

I have bought some air stones which I am running for 3-4 hours a day. The
fish move away from the waterfall whilst these are switched on but the next
morning they are back to gasping on the surface again.
I would like any advice on whether the pond is overcrowded or if the water
needs testing. If the latter what do I test for and how do I interpret the
results.

It does sound like they are short of oxygen and I'd leave the airstones
on all the time, especially at night.

Plants respire (breathe in oxygen and breathe out carbon dioxide) all
of the time. It's just that in the daylight the photosynthesis uses far
more carbon dioxide and releases more oxygen than the respiration uses
so the net result is the release of oxygen and the consumption of
carbon dioxide.

It also sounds as though you have more fish than your environment can
cope with. You don't mention filtration. Bacteria also consumes oxygen
and if you have no filtration to remove the detrius it will be lying at
the bottom of the pond and bacteria will be decomposing it.

Also both chlorine and ammonia can damage the gills of fish and that
will result in them needing more oxygen in the water than they would
require with normal gills.

It's difficult to guess at exactly what the problem is but hopefully
the above will give you somethings to investigate. It would also be
worth testing the water (ammonia, nitrite, nitrate, PH, KH and GH) and
posting the results.

I don't know about the stocking level but
http://www.practicalfishkeeping.co.u...pages/home.php has
calculators where you enter the size of your pond and it tells you what
it recommends.

--
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail ngpsm4 (at) infohitsystems (dot) ltd (dot) uk