i just added 2 koi and a gold fish to my pond. Since putting them in 2 days ago, I have only seen the gold fish briefly and the koi not at all. They seem to hide under the plants. I have tried putting food in, but they don’t come out to get it. I have seen evidence of chewing on the water lettuce. How can I get them to be more social and how long can they go without fish food?