City Fishies

Now and then I stray from the cat theme here at City Kitties and post non-cats.  I think I've only posted mammals up until now, but I've seen this koi pond a few times in my neighborhood and decided that it is worthy of being featured.  I'm not sure if it is clear enough, but there is a particularly large, black fish just below all the small orange ones.

I wonder where they live in the winter?