True, I bet lime is the cheapest and quickest way to kill fish in a drawn down pond.
I know from experience that when fish swim though a cloud of it they jump out of the water and usually die. Just a handful of it will cloud up a 2-3 cubic yard area of water.
But I get what you're saying about dilution. Bleach is very safe for humans and aquatic life unless it's really concentrated. One day a distraught fellow barricaded himself in his house and threatened suicide by drinking 5% household bleach. Well, he drank it and it didn't hurt him but he sure had a bright smile. Don't try that with 5% lye or lime.
