Let's face it -- "Patagonian toothfish" just doesn't have the same tantalizing ring to it as "Chilean sea bass." But that's the official name of the fish found only in the southern seas, which created its own culinary craze stateside beginning in the mid-'90s. In Chile, it's also called bacalao de profundidad -- cod of the depths -- but the only similarity between a cod and the fish in question is its white flesh. So it's not a bass. It's not a cod. Whatever else it isn't, the Chilean sea bass is wonderful at the River Oaks Grill (2630 Westheimer, 713-520-1738), where a pan-roasted version with pistachio and almond crust ($23) gives you something to really cuddle with your tongue. First seared and then baked in a pan, the flavorful flesh is so tender that it falls off into delicious, thick shingles at the touch of a fork. It comes with a saffron sauce so clingy you'd swear it's melted Velveeta -- except for the delicate saffron taste, which creeps between your taste buds and takes hold. The sauce is punctuated with chunks of chopped Roma tomato added in at the end, allowing them to retain their fresh sweetness.