Kingfisher fishing (sort of)

I saw the kingfisher actually dive into the moat on Friday and come up with apparently something in its beak. It flew in and perched briefly on a sycamore twig that is over the water. I saw it dive in and then return to the perch. Unfortunately the handblown glass I was watching through makes everything a bit hazy so I could not be sure what it had in its beak. I can only think that is it is dragonfly larva or something similar as I have never seen fish in the moat.