This weather seems to be pretty good for micro bugs in large areas of water. I was in central park last weekend and grabbed a water bottle full of water from one of the lakes. I have no idea what bugs were in there. Although i dont think daphnia was there, other critters were.
I know that it might be dangerous if dragonfly larvae is in there, but I put the water in a container with only a few fish to see what happens. So far, the fish seems healthy and I dont see anymore bugs.
Bugs I would love a place for more live food as well.