I was was foolish. :'(
I live more or less in what is now the middle of the city. One block off the main east/west route through the city. We have a billion rabbits, but I didn't think we had raccoon or mink or whatever. Something got all my small goldfish and has scarred the Koi to death. For 2 days they lay motionless on the bottom, like fish sticks.
I put a black milk-crate in the middle in the deepest part of the pond and put a lily pot and rocks on the top. This morning the Koi were all inside. They swim around and eat but really stay in a bunch. They hide when I approach the pond. I am afraid to feed them because I want them to stay scarred. They used to come to meet anyone who came near the pond.
I put out a havahart trap last night near where we found a little piece of gold tail. But, had no clue what bait to put in it. The local pond store says there are a lot mink in the area. What do mink eat besides goldfish?
My other question is what happens when they grow to big to squeeze into the holes of the milk-crate? My biggest is only about 10 inches. Some have tripled in size since I got them last summer. Each morning I spy from afar to make sure everyone is accounted for.