How fast do koi actually grow?

This is an experiment to see how quickly Koi can grow when conditions are pretty optimal. I was interested because I’ve been surprised with how long it’s taken some of my fish to grow which I put down to living in a relatively moderate climate in the UK where half the year the temperature is quite low. This experiment confirms that fish to grow pretty quickly when the water is warm!

[@Simon.Bryant]

Nice experiment!
Does your auto feeder handle small amounts of food?
I only feed less than 20g per day but I’m trying to find a feeder that would do say 5g at a time.

[@thekoilab3944]

Yes it’s the fishmate p21. It’s only really any good for small amounts. Here I was having to feed quite a lot by hand in addition. It’s main drawbacks are it only has one feed per day (although that is spread out over 2-3 hours), and the small size of the hopper so it needs filling regularly.

[@wwildridge]

Sadly the design of this experiment doesn't actually tell us anything about the relationship of koi growth and temperature. I'm very curious to see an experiment designed with several groups of similar fish (same starting age, breed, type, length etc) and then having them grow on in different temperatures (16, 18, 20, 22, 24).

[@thekoilab3944]

Yes very fair point

[@shaunleonard8146]

Interesting.😀

[@markred3267]

my tosai grow 4-5cm in a month..feed with high protein

[@thekoilab3944]

Interestingly the kujaku, which grew about 2cm has continued to grow at a pace since I put it in the main pond, at least 2cm per month since and the temp has been 18/19. I can imagine that Increasing temp and pure growth food could deliver 4-5cms. Good work on getting that sort of success with you fish. Thanks