The bird deaths I can't explain, but mass fish kills are extremely common, especially in the colder months. I think people have been a little overly-paranoid. Mass kills are also very common when bodies of water turn over in the fall and spring.

"Dozens of fish found dead in San Antonio, Texas, unknown causes." Jesus, dozens? I clicked on the article and they failed to mention the type of fish. Were they dace or catfish? Maybe even carp?