Being a big fish in a big pond doesn't necessarily make the fish, even in the metaphor, the king of the other fish. The analogy isn't symmetrical. Nor is it symmetrical in "a small fish in a small pond".
You need to find something that conveys a state of authority for the first phrase, "king of kings", where the same phrase can be altered both in the subject and object. "Be a leader of leaders, not a leader of followers, let alone a follower of followers" might work with a bit of alteration and imagination (or actually as is as well).
As to your question, the metaphor isn't symmetrical therefor it doesn't work.