A fantastic fish sandwich requires just two things: fresh bread and fresh fish. As you enter Heads or Tails, you can watch fishmongers filleting your lunch in the retail portion of the restaurant. That's fresh. Grab a stool at one of the long counters that line each side of the room and make your decisions: tilapia, grouper, dolphin, or salmon; cleanly fried or griddled with gusto. Lettuce and ripe tomatoes get fluffed into the soft bun, and on the counter are squeeze bottles of condiment sauces that encompass every major color group but blue. Squirt away and create your own edible Jackson Pollock. This is not only a richly rewarding sandwich but also -- at $4.99 -- a great deal.