it's gonna sound silly to most mfkers but we're literally talking lineage here (though tbh it's almost exactly like the kennel clubs, simply a list of names) . Coloring sure that's a base requirement as is 20"+ (24-28 is ideal). But you get a koi from a solid lineage that has proven itself over and over by spawning several champions and it's going to cost you. Also you're paying for the reputation of the breeder as in if they've spawned champion koi, it's gonna cost you extra to buy from them.
superficial to the extreme, however, the value remains. So when she gets bored of them, she won't lost the cost of the fish, she might even make money on them. Again, show quality koi are akin to Westminster dogs. Will a cool looking one from a local breeder do ya just fine for 50$? totally could you spend 12k on one if you really wanted to also? totally.
