Koi carps are quite expensive in the UK..
In Japan, yes if you want to get specific Koi carps, it’s expensive. But normally you can find them everywhere.
There is a ditch , it’s go through houses in a small town. But the water is very clear and clean naturally ..
By the way, there is no CCTV .. ( lol ). But no one steals them. My British friends say ” If it’s in England, one night , all gone ..”
But I think it’s used to be more Koi carps.. My friends ( live the town ) says “Some people from another countries ( not tourists, they came Japan to “study”, but in fact they don’t study and work illegally. ) , they took those koi carps to eat ! “.. I don’t know it’s true or not.. But anyway I hope we can keep this beautiful town …