(The Spanish, French, and English ways of treating the Native Americans, respectively.)
I think you need to review your history, there, if you feel you can divide up the treatment of natives purely along national lines. I point out the number of South American indigenous casualties courtesy of the Spanish, and I have no idea where the historical revisionism of French-NA relationships began to be recast as some kind of "golden age", which is just bull, they were no better nor worse than their contemporaries. As usual, I'm just going to blame Quebecois seperatistes.
Well, to defend myself, let me grab a little of the context, there:
You could have missionaries that try to "bring the light of civilization to the primitives", have hunters exploring the caverns who trade with cavern civs to get more pelts or the like, or just shove them off the land because you want it. (The Spanish, French, and English ways of treating the Native Americans, respectively.)
While I certainly admit it isn't consistant, after having come out trying to correct a misconception a few posts back, I wasn't trying to start a talk about Native American history here, and was just giving out some tongue-in-cheek references and very sweeping generalizations for the purposes of humor and to illustrate the idea. I certainly hope that someone wouldn't take what I said about the Spanish being on a mission to "bring the light of civilization to the primitives" seriously.
With that said, I honestly don't know nearly as much about the French relationship with the Native Americans as I have read about the English and Spanish. However, even with the French, I was only trying to imply a self-centered indifference, not a "golden age" of any sort.
Regardless, this is still not very relevant to the topic of what would be an enjoyable gameplay mechanic for Dwarf Fortress, and I can't see this line of conversation going anywhere particularly good.
So, to get back to what Solace had said, what would you want as a way of dealing with
every foreign civ that might happen to be co-occupying the embark, which might be different from what you would necessarily do with the fish-people.
Also, considering some of what's in Army Arc/Kingdom Arc, we are supposed to be able to have expeditions of our own that send back supplies, so perhaps having the ability to do this with fish-people in the nearby caverns might be possible.