We recently installed a small garden pond in the back yard and stocked it with a few small koi. Now a couple of the koi are missing. A friend suggested that raccoons have been eating them. How can I tell if he is correct, and if so how can I keep the raccoons out of the pond?
Since the koi are missing, you might not have a raccoon problem, but a heron problem. Raccoons won't eat the whole fish. They'll leave some scraps behind. Herons, however, will gulp down the entire koi.
To prevent herons from doing more damage, buy a heron decoy to set in or near the pond. You might find one at a garden center that carries pond supplies, or online. Real herons will avoid your pond if they think another one is already feeding there. In the mean time, temporarily cover your pond with bird netting like you would drape over berry plants. It's not very attractive, but will prevent herons from eating all the koi until you obtain the decoy. Cover your pond soon because it doesn't take long for a hungry heron to eat all the koi.