I'm guessing the one that looks like the flag of Japan must costs hundreds of thousands.

I'm interested in Koi fish again after watching a feature on TV about it. Does anyone know how much it would cost to build a 3 ft pond and an estimate of how much I need to spend for maintainance (food, cleaning the tank etc)?

My neighbor also has pesky cats so do you think it could kill the fish even if it's in the pond?