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Must I heat my Pond? - What's the
best method? Well
frankly - NO - you don't have to heat a koi pond. Koi are
poikilothermic, which means their body temperature is governed by the
surrounding water temperature. They are hardy 'coldwater' fish which
will withstand and proliferate in a wide range of water temperatures.
Koi have been known to survive temperatures of 1 Deg C (33 Deg F) up to 32
Deg C (90
Deg F) without ill effect. It is not the extremes of
temperatures which seem to bother Koi, but rather the duration of any
temperature extremes which can cause problems for the Koi keeper.
In the UK, the problems are generally
not associated with extremely cold water temperatures during winter, but rather the length of
our rather dreary, 'cold' and miserable winters and low water temperatures which cause problems.
A Koi's immune system functions properly at temperatures over around 12.5
Deg C ( 55 Deg F). Under this and the immune system ceases to function
effectively and at lower temperatures, a Koi's ability to fight diseases can
be severely reduced. Unfortunately, many pathogenic bacteria and a
range of parasites can survive and even proliferate at temperatures down to
around 5 Deg C, meaning that your Koi are at their most vulnerable at
temperatures of between 6 Deg C and 12.5 Deg C. As water temperatures
in the UK can be in this range for up to 5 months of the year, you will
appreciate why it is that most of the disease problems with which we as Koi
keepers are faced (generally in Springtime) may be precipitated by this
length of relatively cold water temperatures.
In addition, smaller ponds of
say, 2000 gallons or less will be more prone to the affects of unstable
water chemistry as the pond volume is comparatively small. Even in
ponds with a larger volume but of a shallow nature can exhibit the same
problems. Any water parameters which changes too quickly will stress
the Koi. One of these water parameters is obviously water temperature,
and ideally, this should not fluctuate by more than 0.5 deg C per day.
Over winter, and indeed in Spring, we may get very cold and frosty
nights, but followed by sunny days, which can result in temperature
fluctuations of up to 2 deg C or even more in small, unheated, shallow and
uncovered ponds. The degree of temperature change obviously varies across
the UK but one of the most important benefits of heating a Koi pond is the
ability to achieve a stable water temperature at all times.
The objective of any heating
installation is therefore not to heat the pond to high temperatures for
reasons of, for example, high growth, or just to keep our koi active.
It should be targeted at controlling the water temperature to avoid the
temperature 'trap' or fluctuation described above.
In our own installations, we
heat our stock (and private) ponds until Christmas time, by leaving
the pond thermostats set to 16 Deg C ( 61 Deg F). This extends the Koi's
Summer and keeps them feeding and growing well. From around the
turn of the new year we then progressively turn down the temperature by 1/2
Deg per day until the water temperature returns to ambient levels (whereby
the water temperature falls to match the surrounding average air temperature).
We then give all our Koi a shortened winter for about 1/2 of January and all
of February and then switch the heating on again at the beginning of March.
During these cold months we allow the water temperatures to drop as low as
we can , normally down to 3 or 4 Deg C. This does absolutely no
harm to healthy Koi for this short period but helps to 'cleanse' the pond
environment and kill off any remaining parasites or bacteria.
This means that we are effectively
giving the Koi a 10 month Summer and a maximum two month Winter. We
are also only using our heating systems for around 4 -5 months of the
year, and not heating at all for the two coldest months, January or
February, and since we are not trying to raise our pond temperatures to
ridiculously high levels, we are also reducing extra fuel bills as much as
possible.
It is an established and accepted
fact that Koi live longer if given a 'natural' winter, and we do NOT
subscribe to the view that Koi ponds must be heated all the year round to
ensure their well being. Indeed we would go further, in that ponds
that are heated all the year round must be maintained much more carefully to
avoid problems as the Koi never get a period of 'rest' or inactivity and a
Summer maintenance regime is absolutely vital to ensure that no
problems are encountered. Weekly water changes and filter maintenance
must be adhered to whilst water temperatures are elevated simply because
whilst you are providing a warm comfortable environment for your Koi,
you are also providing the same conditions for parasites and bacteria which
can and often do multiply very quickly in ponds kept 'warm' during winter,
whilst the not so vigilant Koi keeper is snuggled up in front of a log fire
with ample supplies of mince pies and Brandy, completely forgetting about
daily or even weekly pond maintenance tasks!
If you do decide to heat your pond
you will have a number of options, including heating using Gas, Oil or
Electricity. Whilst Gas and Oil installations are more expensive
to install, they are comparatively cheap to run. Electric
systems are easy and relatively cheap to install, but more expensive to run
- the choice is yours!
To give you an idea of costs,
Gas or Oil systems can cost as little as 20p per thousand gallons per day to
run, whilst Electric heating costs start from around 30p per thousand
gallons per Day.
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