During the past few weeks, the enquiries we are getting have changed from the usual warm weather bacterial / parasitic / water borne problems to low temperature related difficulties.

This week, we have encountered a Koi on its side in an above ground vat at Southampton (water temp 2.2deg.C.), visited Milton Keynes with a similar Koi on its side in a shallow pond (water temp measured at 1.0 deg.C) and as we write this article, we are dealing with a 24” ‘sided Koi’ in Cheshire – again almost sub-zero pond water temperatures.

Despite what you may have read, once the water temperature gets below 2- 3 deg.C., your Koi are at severe risk.  At this temperature, all the life giving functions have slowed right down and survival is a challenge to any Koi who is not in a good healthy condition.  One major problem which often occurs is chilling of the swim bladder which impairs the buoyancy of the Koi.  The only way to correct this is to warm up the pond water slowly, if possible or alternatively, transfer the affected fish to a warmer environment (i.e. quarantine tank).  If the Koi is left on its side, it will deteriorate and often, fungus takes hold.

Should you start to have problems:

In an emergency

1. If fish are on their side, undertake a 25% water change.  Your tap water will be in the region of 8- 9 deg.C. at the present time.  Remember to use a purifier or de-chlorinator.

Precautions you can take include:

1. Put in a small heater (if the energy costs are affordable!).
2. Bypass any waterfall to avoid further cooling and turn off any fountain (provided they are not the only sources of air)
3. Turn down the air but make sure you leave a reasonable amount  in your pond. There is still an oxygen demand in the winter by your Koi, filters and system.
4. Cover the pond to reduce heat losses but make sure that you leave an air gap of at least 4” and ventilate under the cover.
5. Should the surface freeze, melt a hole in the ice.  Do not smash a hole through the surface.

If you are not sure what to do, give us a call and ask for advice. We are only a ‘telephone call’ away.  If you do not have an accurate digital thermometer, we have many inexpensive ones here and we can send you one.

Good luck with the winter and hope to see you soon (only socially we hope!!!)

Rod, Gerry & Dave Isted

Healthy Koi Ltd

01243 572762