I have noticed two toads in and around my pond lately, and I am only seeing one of my five 4" koi and only after dark with a flashlight. It does not come out during the day.

They were introduced to the pond a week and a half ago. Either they are hiding, or something has gotten most of them, since I haven't seen any bodies either floating in the pond or lying around the edge. The one I'm seeing is very skittish, and flits from one hiding area to another in my flashlight beam. It could be a "settling in" period, but I'm starting to wonder if the others are even still in the pond.

I use a Scarecrow during the day to help guard against herons, but have never seen one. Pond can be seen from both the living room and the kitchen, and family members who are at home during the day say there have been no large birds around. The pond has no shelves for a heron to utilize, and places for one to approach are limited, since it's a small yard with close fencing. A shed is close on one side, a vegetable garden fence on another side, with no real open space. There is also a "cat fence" (strong netting attached to curved brackets) around the upper part of my wooden fence to keep out stray cats, and it has been extremely effective.

So, I'm turning to the toads as possible culprits. Can and will a three or four inch toad catch and eat four inch koi?