Amazing footage! That looks like a huge (a fully grown pike? Aren’t they predatory fish with sharp teeth??) fish the bird caught! The fish was struggling, but the hungry Heron managed to fully consume (alive?!) it all okay? It looked like the unlucky thing was still desperately kicking inside too! I wonder, does the large fish stand any chance of escaping if eaten in that condition? Maybe it can turn around inside the elastic throat/stomach and has a chance of survival here.