well prepared monkfish in seattle ?
You can buy it from H-Mart.
Then learn to cook it yourself. Earn yourself some cred!
Or eat the liver (ankimo) at Fuji Sushi (or some other sushi joint, but i like Fuji). But as far as the whole fish goes, it's been harder to order. My favorite Korean restaurants sometimes have it, but don't order it when it's not at its most popular.
And enough with the Seafoodwatch.org links, people. Did the OP ask for that? Nope.
31217 Pacific Hwy S, Federal Way, WA 98003