I agree with ewest. Very short time period, and when the water turns clear, most the damage is done. I usually see some piping before the fish die. I drain the pond as low as I can before I apply HL, so I haven't seen and dead turtles or frogs. They're usually out after I seine.
Hydrated lime is nothing to play with. Stay upwind and wear all the silly advisory stuff. I never apply it without goggles, gloves, chest waders, and long sleeve shirts. Chemical burns kinda sneak up on you, so I also change clothes and take a shower after I do it.
Be sure to also spot treat any footprints, nesting beds, or any other depression that holds water. You'd be surprised how many small fish can live in a water filled footprint.
