ardesia said: I am curious, why don't you keep fish in your pond year round?
Unfortunately, the wildlife removes the fish from my pond over time. I only put a few large koi in last year, but they all disappeared by this summer. The big blue heron are the primary culprits, and even when they can't possibly pull the fish out, they still spear and kill the fish with their long, sharp beaks. This is a front yard display pond, so covering the pond rather spoils the effect, and in order to stop the heron nets need to be very strong, and well supported high above the water, because our herons will tear them up and poke through the holes trying to snag fish. I was going to put a motion detecting sprinkler over the pond this year, until I discovered I had nothing left to protect. At least they took them entirely this time. I always hate finding the fish gasping with bloody holes in their sides.