What eats water lilies?

I have a natural pond into which I have planted 3 different kinds of water lilies. Two were small when planted, the other was quite large and flowering. When I checked back on the health of these plants a week later, I saw that something had eaten them back to the roots. I know there are catfish in the pond, and we occasionally see ducks. Would either of these be the culprits? What else would devour a water lily?

Ducks love waterlilies. Geese too.

Thank you, Dale. So now I need to decide between ducks and waterlilies. Tough decision :)

You could try caging the plants. Build a cylinder of chicken wire or 4x4 mesh (whatever makes sense for the size of the ducks and plants, depth of the pond, and your motivation). The water and fishes go in and out, but the birds can't reach.

Water-living turtles will also eat water lilies, if they're part of your pond environment.