Question
I have the same problem as teresa. Lilly pads are severed at the stems(about 20 -30 pads) also about 5-6 pads have square holes in them. The pond is cement about 30 years old -above ground with another pond abutted in the ground 500 gallon and 1000 gallon. The pads are not eating and it does not look any are missing. I did see in my yard (about 1/2 acre) a snapping turtle(turkey platter size).Why he would get in the above ground front pond and not in the back inground pond  where the lilies are fine? What else could be the problem?

Answer
Hi Leland,
Thanx for your question.  In my subsequent research I have learned (I've never had the problem myself) that there are beetles that will feed on water lilies or bite through them when breeding.  There are also worms that are specific to water lilies.  Methods of control include brisk sprays of the garden hose (to knock off the insects), hand-picking and certain mosquito dunks (available at garden stores with water gardening specialties.).  Turtles, deer and other animals can also nibble on, even sever the leaves of the plant.  The infestations sounds more insect to me than anything else.  Spend some time closely examining the plants.  Look to see if you can determine how the leaves were severed and look to see if any insects are in the infested area.  You may catch some in the act.  If you have a night light on the pond.  Turn it off for a few days to see what happens.  Let me know and we'll go from there.
I hope this helps.
Tom