I like where this is going, but when I think "mysterious and heroic" I think of:
The Lone Ranger, Zorro, and Nate Odoms as my top 1, 2, and 3's. So the trick is how do you import the best qualities of the Lone Ranger, Zorro, and Nate Odoms into the Fishheads. Probably they need someone, an ally, like Tonto, a young boy, or Darryl Talley to communicate the hero to the outside world.
It is important for the fishheads to be able to travel incognito and not have to fawn over the superficial attractions of fleeting fame. They must be noble, yet wise to the whims of the basest insticts of Mankind.