Every year around about this time, the Koi in my ponds decide that it is time to go through the annual mating ritual which is pretty dramatic to watch and for the fish involved. My little dogs obviously thought so as they barked very excitedly at the spectacle.
There is nothing gentle about it especially to the females and it is made worse by more than one suitor at a time. In fact, it is not a bit uncommon to see a single female being chased by a half dozen of the opposite sex all pushing and shoving and literally bumping the female in an effort to induce her to drop her eggs which they will then fight over to fertilize. Once dropped, the eggs, of which there are several hundred, can be fertilized by several different males and only in the case of selective breeding under controlled conditions by Fish Breeders are there any choices made.
The movie shows just how aggressive the males become and there is always an element of risk involved for the females. A few years ago, I had one female jump clean out of the pond and before I could get to her, Richie, one of my dogs had grabbed her and ran off down the garden. By the time I reached them, the dog had taken a large chunk out of the fish’s head. This year, I did not have anything quite so dramatic but did have two of the large Koi die, one in each of the big ponds probably due to egg binding or some other related problem. The big female Koi in the video are all of 24 – 36 inches long so are pretty big.
When all of the eggs are laid and fertilized, some semblance of peace returns to the otherwise tranquil ponds. The eggs themselves are at risk from getting eaten by the Koi themselves or by any turtles that may live in the pond. Even after the remaining eggs hatch out, the fingerlings are still subject to getting eaten by their elders and by the same turtles and in my case, Brown Snakes of which there are two that live in the ponds. So, for all of the hundred of eggs that get laid and are successfully fertilized, very few will ever make it to grow into larger Koi. This is not a bad thing as there is such a thing as too many fish in one pond.
Now it is a game of wait to see if any of the fingerlings survive. Next year, we will do it all over again as such are the ways of Nature.