Can you help with gender please?

[BenDalat]

Hello all,

I don't have a net yet, and I'm not good enough to check the gender of my koi by seeing them.
Can you help, please?

The left one was born in 06/2020.
The right one was born in 06/2021.

[NaturalK]

Man, I am always so impressed by that huge one on the left. What did you feed that thing?
I think it's male and the one on the right is female.

[BenDalat]

Man, I am always so impressed by that huge one on the left. What did you feed that thing?
I think it's male and the one on the right is female.

Thank you NaturalK.
I feed them Nijikawa koi food.
I think it is genetic.