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Guest Blog Post - Koi Carp in the Winter

21st Nov 2019

As humans, we have simple methods of protecting ourselves during the winter months. Wooly jumpers, scarves and gloves are great for keeping warm and allow us to function as normal.

Koi carp, on the other hand, don’t have it so easy. As they’re not native to the UK, they can struggle to deal with the fluctuating temperature levels; unfortunately, their systems begin to shut down when water temperatures drop below five degrees. This is nature’s way of allowing the Koi to cope, limiting their energy levels.

So how can Koi carp keepers protect their fish warm during the winter?

1. Heat & Covers

Hozelock Pond Heater 100 Watt

An effective way of looking after your Koi when temperatures drop is to invest in a heat exchange pump or electric heater, such as the Hozelock Pond Heater 100 Watt. Although it can seem like an expensive choice at first, purchasing a heat source pump will actually save you money on heating bills in the long run.

A cheaper source of warmth for your Koi is to cover your pond with polycarbonate sheeting, preventing wind-chill factors, ice formation and snow in and on the water. This type of sheeting is essential for the winter months, along with the fact that it’s versatile and affordable too.

2. Salt

Once temperatures have dropped, salt can be used as an effective tool in safeguarding your Koi carp. Distributing a small amount of salt (around 0.5oz per gallon) over a period of days can ease the amount of osmosis pressure on the Koi and lower the freezing point of water. This means that they can concentrate on their immune systems.

However, this salt solution should not be used for a prolonged period of time, and adding too much salt in one go can shock the Koi, along with the filtration system. So make sure you approach this with caution and only try it if you have some accurate measuring equipment to hand.

Bermuda Floating Pond Thermometer

3. Digital Thermometer

Acquiring two thermometers is ideal for your Koi. One should be for the temperature of the water and the other for the outside ambient temperature. Your outside thermometer will allow you to grasp, at some level, where the weather is heading and what you should be doing in preparation for the colder weather that may come. An ideal thermometer for your pond is theBermuda Floating Pond Thermometer.

Once there is a decline below 12ºc, you can take precautions and heat and cover your Koi.

4. Treatments

It is a good idea to use a good general-purpose treatment, such as Forumulin and Malachite Green, before the cold snap sets in. Any issues that Koi carp suffer from normally can fester during the colder months and worsen, becoming harder to treat. If you treat this beforehand, you reduce this risk and can ease problems for the Koi through the cold weather.

5. Final Tips

Make sure you move any aeration discs that you have in your pond to the upper levels of the water, which leaves a stable environment underneath for the Koi to sit.

You should also make sure you do not overfeed your Koi, because cold temperatures can cause their metabolism to lessen, at which point they lose the ability to digest and process high protein food.

On top of this, you should make sure you are continuing to monitor the Koi as you normally would; any changes in their behaviour or appearance should be treated with caution and don’t hesitate to seek professional advice if you have any doubts as to your Koi’s health and wellbeing.

This post was written by Shaun Mitchell of Mitchkoi.