Need help in koi breeding

Koi fish breeding, need help?
I want to ask about koi fish breeding.
I always face the same problem when I do breed my koi fishes.

I use the method of isolating a female fish with a male in a separate
tank. The process of spawning happens normally and the female lays her
egg. But the problem is that I am not sure if the male had thrown his
sperms over the eggs. I can see the eggs in my spawning ropes, but not
sure if the male released his sperms. My question is: can the female koi
release her eggs and those eggs are not fertilized by the male koi
sperm?

I close the filter and use only oxygen in the tank.

I usually wait for 5 days but nothing appears from those eggs. In fact,
there is an awful smell coming from the tank and there are some white
substance floating on the water tank. Please need your advice? How can I
complete the breeding process?




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Dxbuae