Alligators rarely attack another that is of the same size. Unless a female is involved there’s no point.
This time was looking to be an exception. Another Alligator, not seen here, had caught an Anhinga. All the bigger Alligators went to investigate if there was anything in it for them.
These two started swimming in circles around each other. You can see the ripples in the image above.
Nothing further happened and the group moved back to the island in this swamp. Where they all seem to hide together.