Well, I can tell you about one little puddle in LA that probably doesn't have any fish... and that's
Macarthur Park. I went by there after work one day and checked it out (I work in downtown LA)
and that place was putrid... I could see the bottom along the banks and it was full of trash and
what not. No signs of any vegetation not to mention fish... and the smell was horrible.

I wonder if Echo Park is any better. Seems to me they actually plant trout in that little urban pond.