User blog comment:Woohoot/The potential of Fishmen/@comment-3345720-20150708154150/@comment-10543621-20150710014523

I think the whole deal with Haki and fishmen is probablybecause fishmen karate already grant the advantage of being able to overcome DF ability, which in a way makes Buso kinda unnecessary. It's kinda like different means to achieve the same end.

As for other forms of Haki including Haoshoku, I'll agree that we can only wait and see. Afterall, the majority of the fishmen we've seen are inhabitants of the fishmen island. Strong individuals tend to travel the world rather than stay at their home land. So there might be other strong fishmen out there like Namur as you've mentioned.