Just because you haven't seen them, doesn't mean that raccoons are not in the yard.... They are everywhere and plenty of them too. I've only seen them once or twice, but their destructive habits I've had plenty of. They love water and they love fish. Cats may enjoy fishies, but they don't generally like water. Unless the pond is extremely tiny and shallow or the fish congregate at the edges waiting to be caught something else is likely doing the fishing. Around here people also have problems with herons visiting their koi ponds.