No experience with Koi myself, but..

[oceandeep85]

http://www.boredpanda.com/abandoned-shopping-mall-fish-bangkok-jesse-rockwell/">http://www.boredpanda.com/abandoned-shopping-mall-fish-bangkok-jesse-rockwell/</a>

pretty awesome read.

I suppose in a life after people, there's going to be a hell of a lot of Koi.

 

[rizmaher]

The fish don't look like catfish or koi. I think the fish are something similar to tilapia.