I've been to Six Feet Under's location near Georgia Tech a few times; I finally made it to their original location near Oakland Cemetery. This is one of those destination restaurants in Atlanta. The Georgia Tech location is amazingly similar to the Oakland location---the proprietors clearly decided xerographically duplicate their quirky, offbeat style in the new location.
The fish has always been excellent. The calamari is excellent and accompanied by fried zucchini. It's a festival of fried food---don't order it unless you have your posse with you to help finish it off. My salmon was juicy and flaky on the inside with a crispy crust on the outside, not the easiest trick in the world. Don't let the BBQ salmon idea fool you. It isn't covered in ketchupy sauce, but rather something more akin to a salsa. I can't tell you exactly how spicy it was because I also ordered the fish stew which transported its welcome spiciness to the main course. The fried okra was of the full-pod variety; there's clearly a full-pod-okra underground that I've been unaware of for the past fifty years.