You probably already know that brining meats and seafood boosts their flavour and moisture. Two lesser known reasons to brine seafood in particular are that the fish will look better and be easier to grill.
Food & Wine Magazine notes the technique of chef Bryan Voltaggio (of Volt and Top Chef fame). By soaking fish for 10 minutes in a sea-salt brine (1 tablespoon sea salt per 4 cups of cold water), he keeps fish on the grate from falling apart.
Even if you're not grilling, a quick brine will get rid of the unsightly patches of white albumin that forms on fish when cooking. According to Cook's Illustrated:
Just 10 minutes in our standard 9 per cent solution (1 tablespoon of salt per cup of water) is enough to minimize the effect. The method works in a similar fashion to how a longer soak improves moisture retention. The salt partially dissolves the muscle fibres near the surface of the flesh, so that when cooked they congeal without contracting and squeezing out albumin.