Crocodile Evolution?

Are crocodiles evolving before our very eyes? When you think of a dinosaur, you may think of a crocodile or an alligator. Big scaly lizards and as far as we're aware, they were derived from something more aquatic, like fish. Fish with fins. Is it possible that crocodiles are going back into the sea? Or is this fin mutation unlikely to tread water? Let me know in the comments what you think!