Really pretty! Music is haunting in its own way, though obviously the limits make it a little repetitive.
I was able to beat it after a few tries, but I do wish it was a bit more forgiving, if there was some way the white koi's turning radius could be tighter than the black's, or of the number of scales you'd lit up didn't totally reset. Ends up being more frustrating than calming at times, haha.