Are these the first fish put into the pond? that's a pretty hefty load for a new set-up. Right now your biological filtration is really not doing anything, it will take 4-6 weeks after the pond was set up for that to establish itself. in the meantime food can be a big enemy. Make sure they eat it, if it's still there in 10 minutes net it out. Do Not Leave It! When they feel secure they will start coming up and eating but again, until the bio-filter is working good feeding can cause more harm than good. be very careful for right now. my suggestion get a good test kit and a note book, test your water every few days, keep track of it and watch what is going on. You'll see when the ammonia starts rising, then nitrites, then nitrates. all of this has to happen. In that time you will learn about what effects your water which also effects the fish. less than 5% of all pond fish will starve, over 75% die due to human error one one kind of another and of that I would have to say 50% of those are caused with us and feeding in one way or another. To somewhat answer your question it can take from right away-2-3 weeks for new fish to get used to their new surroundings and come up and start eating. In the winter they can go for months with no food at all. So only feed a few pellets, give them 5-10 minutes to eat and then remove. don't stand over them, if you want to be close and watch sit low to the ground until they get to know you. At first they think you are a predator so they will avoid you until they figure out that you, means food.