As far as Northern Water Snakes or Red-Bellied Snakes that live in the Northeastern US, smaller water snakes might be eaten by a raccoon, heron or hawk. There are other water snakes in other areas of the world, so this is a broad question.
yes they do eat fish and many other sea creatures like squid ,baby alligators, and sometimes even chickens if they are near water
Simple answer is no.
fish and frogs
hawks
They will eat anything from baby fish to full grown frogs.
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