If you will have a car and don't mind driving over to Titusville, the best seafood IMHO is at Dixie Crossroads.
We don't make a trip to FL without eating there at least once! I grew up in FL and miss eating good seafood. DC takes care of me!
A couple of years ago, I heard they also had a restaurant on I-drive. I don't know if that is still there, and I never ate there so I can't speak for how it compares to the Titusville location.
I can tell you though, it is definitely worth the drive to Titusville!