Japanese longkang so clean that koi fish are living in them

[crispy]

I saw this recently and I'm so fascinated. There are some towns in Japan that have such clean drains that expensive-looking koi fish live in them!





Is it possible to achieve this in Singapore? 

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A video of the koi swimming around in the drains.

each fish must be a few hundred dollars!
i think if our drain has such fish, the drain will be empty very quickly.