The amount of time is hard to predict. The amount of oxygen held in warm
water is much less than in cold water. The activity of the fish is higher
in warm water than cold water. Submerged, so called oxygenator, plants use
oxygen at night, and provide oxygen during the day. And of course, due to
the health of the fish, the gills can be compromised by parasites, ammonia,
nitrites, and any number of other factors. Everyone needs some form of
battery backup or backup generator. For battery backup, I started with a
boat bilge pump and a battery. Some of the sporting goods stores or
sections of stores have battery operated bait aerators. Both of these
require you to be there when the power fails to activate them. I currently
run a large air pump through a battery charger, battery, power inverter so
that it is always running from a fully charged battery, so it is on even if
I am not home.My system will go about 18 hours. I also have a portable
generator that I bought specifically for the pond in the event of a major
power outage. Of course I run an extension cord into the house to run the
refrigerator and freezer and make a pot of coffee, but the generator is for
the PONDS.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"DonKcR" wrote in message
news:TPV_a.1692$QT5.1149@fed1read02...
Gary, That brings up something I've always wanted to know, how long do you
think that the power could be out for till your fish are in danger? I have
a
750 - 800 gallon pond and 10 Koi. I always worry about that every time we
have a big storm here in Arizona. Thanks Kc
"Gary Rich" wrote in message
...
Carl Beyer wrote:
OK, Take out the filtration factor and what is too much for koi?

The reason I ask is that I see so many different claims, and then I go
see a koi breeder and they have 20 big ones in 1000 gallons (30+
inches). And 50 or more in 750 gallon setups...

The main reason is, like others said, fast turnover. Those fish are not
crowded in that tank for that long. And they filter the heck out of it.
The latter point also equals risk. If they had a power failure for
an hour or two probably all those fish would be dead. They probably
have battery backup, since they know this. Do you? Lower stocking
rates means that the filtering can fail for a longer amount of time
before it's terminal.

garyr