It wasn't hard at all as long as the pond is deep enough per my earlier comments and the fish are not freshwater tropicals (we've had comets, shibunkin, and koi make it through without any issue, including deep freezes of 10F/-10C lasting a week or two). Keep the pump on all winter for oxygen. Remove the taro to a filled bucket and stick it on a sunny shelf inside.

Once the temp drops below 40 degrees F (~5C) the fish go dormant, usually under some dead leaves at the bottom or in the cinderblock we have at the deep end. When ice forms they will be fine, as the bubbling pump keeps an open spot for oxygen (it should be bubbling about 1 inch above the water line and not splashing outside the pond liner). If it's a deep freeze and the pump forms an ice bubble, break it open with a hammer. The rest of the ice can stay on the pond surface.