Ever had monkfish? Go to the average Western seafood counter, and it'll come described as the poor man's lobster. A firm white fleshed fish, when cooked appropriately, will flake into strands resembling cooked lobster. It's also one of the few fish that will hold up to being made into a New England style chowder.
Of course, that's just talking about the filleted fish. Rarely do people see the whole monkfish, as it is an slimy, grayish brown affair, with an enormous mouth. In fact, what is sold as the fillet is just the tail flesh; in Japan, what is prized is the enormous liver that dominates the inner cavity of the fish.
Called ankimo in Japanese, the liver has an unctuous yet marine flavor, and requires some acid and some sweetness to balance it out. It really is a rare treat to try if found fresh.
I had the opportunity to try ankimo at Sushi Sasa (warning, it's one of those Flash only websites - I should join the ranks of food bloggers decrying stupid website design for restaurants) in Denver last night, and they did a stellar job with this unusual ingredient. They claim to fly it it from Tsukiji; I doubt if they'll be catching it fresh from the Rocky Mountains :). They seared rounds of the liver, served it with a creamy wasabi sauce, and micro greens, a few drops of balsamic reduction (not sure if this was necessary) and strawberries - the last being a pretty clever pairing, as the sweetness and the acid of the fruit paired very well with the fish liver.