I've been out of salt water tanks for a few years, but check out Saltwater Paradise in Irving. Off O'Connor north of 183.
Extremecorals.com is run by the same guy in some massive (10-15 thousand gallon) stock tanks next door and you can do pickups for web purchases.
When I was last in there, they had some beautiful exotic pieces - i was into corals and zoos, but my wife loved fish and they usually had enough stock to keep her from seeking other stores out.
HTH,
Chris