I've got a dog that lies to get in the water too... but he doesn't hunt fish. But your dog is, in fact, a carnivore, right?
Well.... mine's a bisquit eater :) He does like meat... but he doesn't hunt fish. And seeing his foot prints heading into the pond wouldn't tell you that he was there to hunt fish for his meal.
50,000 years from now they could find human foot prints heading into the water.... but that doesnt' mean that they have gills.