I'm creating a fishie whose body I'll smooth bind to skeleton. It's going to be swimming through the water so I was trying to figure out the best way to deal with the fins. I want them to sway in the water so I've been playing with a turbulence field - I connected it to a lofted surface I converted to a soft body that I'm using for a fin and it seems to be working okay. My plan is to use the turbulence field as a cube shape and affect all of the fins (who are separate pieces) at once. I guess I'm just wondering if there's a way to honor the actual space in the water somehow so if I move the fish (say in a 90 degree turn) its fins will move realistically without me having to keyframe the turbulence attributes myself. The way I'm doing it seems sloppy but maybe it's not as bad as I think? :-P
Since you have converted the fins into soft bodies, you could achive the effect you want using goals and goal weights. Check the Maya documentation for details.
From my (limited) experience, I have found that converting the main object into a soft body limits the range of movements. So you'll have to setup diffent goal weights if the fish is moving slowly and different if you want the fish to move fast otherwise the fin movement would either be too subtle or would have over exaggerated deformations.
I recommend using Spline IK instead. The curve for the IK could in turn either be soft body with goal weights or a dynamic curve. You might even want to use more than one bone chain per fin.