"Koi" is a Japanese word, so I'll just let stereotypes take care of the rest of your answer.

I will not search for it, and i cannot be 100% sure about the koi, but there is porn where the sex animals, and then eat them. I think it's called genki porn, rough translation: energetic porn. Proper translation: wtf japan.

Yeah I saw a documentary on it some time ago, and it was actually pretty cool looking, like very HR Geiger but with Eels and turtles and roaches and worms and stuff. I mean, someone's fapping to it and it ain't me, but I made a few non-pornographic drawings inspired by it.

Yeah.