McCormick & Shmick is good, located at Milennia Mall.
Bonefish Grill and Moonfish are on Restaurant Row on Sand Lake, easy to get to from FL Mall. The Samba Room would be an excellent choice, though they aren't a fish/seafood place exclusively, the menu leans heavily that way, and it's a fun atmosphere.
Seasons 52 is one of our favorite local restaurants, and is also on restaurant row. They usually have a couple of fish entrees, but with only 8-10 entrees at any given time, but it's not a fish or seafood restaurant by any means.
Don't forget Blue Zoo at the Dolphin, great food and service and a peaceful atmosphere. While they offer non-fish/seafood as well, the menu leans heavily towards fish and seafood, and the decor accentuates that.
Many of those are chains, but in general they aren't huge chains, and many don't have locations outside of Florida.