It seems to me that all the fish you have mentioned is fried? While I do eat fried fish on occasion, I prefer it be cooked in a different manner.
Preston's restaurant in Lexington and Leoma has a good fried catfish, but my favorite there is the blackened catfish filets.
You did mention Captain D's, When I go there I always get the broiled salmon, I usually get it on the salad though they don't have my preferred salad dressing.
Logan's roadhouse has a great grilled salmon whereas I get it on a salad as well and they do have my favorite dressing.
Newburn's is well repudiated for their catfish (fried is the only method though).
I did have the chance recently to eat at the Swamper's lately and I had a Ceaser salad with a slab of salmon on it.
These are only a few of the locations I have been to.