How, when and why to feed your Koi
The Comprehensive Guide to Feeding your Koi, Happy Koi Style!
It's all about the temperature...
We of course assume that you already have excellent filtration and a pond that is not overstocked.
When it comes to feeding your Koi you have to change your mindset a little from the energy inefficient gas guzzling land lubber that you are.
Koi are fish and they play by a slightly different set of rules than we do. Your Koi are far more dependent on their environment than we are - perhaps this is better described as more in tune with their environment.
As warm blooded creatures, when the temperature goes down we can do something about it. We can maintain our body temperatures and we burn energy to do so. In winter we eat more since we are using more energy to keep warm.
Koi on the other hand do not have this problem. As the temperature drops off so their metabolism slows down. They do not have a constant metabolism like we do and so their energy usage pattern differs.
Because this pattern differs and because food is a source of energy so the food intake of Koi differs according to water temperature.
There is also not a linear relationship between a Koi's energy demands and water temperatures. For instance a drop from say 26C to 20C may result in a 10% less energy consumption by the animal owing to its metabolic rate slowing down. But a temperature drop from 20C to 14C might result in a 90% reduction in metabolic activity. Note that these figures are not exact - I use them by way of example.
Metabolism at low temperatures
What is true is that below 20C Koi no longer are in optimum growth mode and they do not require a massively high protein content food. Below 14C the Japanese tend to cease feeding completely although in South Africa we recommend the threshold of 12C as being an appropriate temperature from which to cease all feeding.
Once you have stopped feeding, stop! Do not feed if the water warms up for a week or two - leave the Koi off their food until spring when the water temperatures warm up again.
The optimum way to feed
Our experience has shown that the way to feed Koi is as follows:
From 28C and above - Saki Hikari Basic but at reduced quantities (50% of normal) - such water temperatures are getting very high for Koi.
From 22C to 26C - Saki Hikari Growth. Feed in spades - as much as the Koi will eat. The more often the better - a few small meals a day is better than one large one. You can pretty much feed as much as your filtration can handle.
From 22C to 20C - you can come off the feed rate a little. Often your Koi will not seem to notice and will feed as ravenously as ever but in theory you should notice your large jumbo Koi eating slightly less.
Below 20C to 12C - Saki Hikari Basic. As the temperature drops below 20C reduce feeding by half and by half again when it passes through 16C. If you like you can stop altogether below 14C or else below 12C.
Koi will still eat food below 12C but their metabolism will have slowed by such an extent that the energy benefits that they derive from their nutrition are likely to be minimal value.
You are not, sadly, going to get any extra growth on your Koi of more than a few grams on your Koi once the temperature drops below 16C. Koi do not grow all year round - they grow when the water is warm.
Seasonal growth is healthy
Cold spells are perfectly normal for Koi and it has been demonstrated time and again that Koi grown year round in warm water do not necessarily demonstrate better growth/quality than Koi grown in ponds where the temperature cycle is allowed to follow the natural rhythms of the seasons. So relax, calm down and let your Koi get on with things at their own pace.