Magikarp are difficult to prepare, as their scales are extremely strong, though once they've been descaled and gutted the meat tastes similar to salmon. Many speculate that Magikarp are actually one of the most-eaten fish-type Pokemon, since they show up just about everywhere.
Whale-like - which, as anyone who has eaten whale can tell you, is absolutely delightful. It's like a weird mix between a nice, rare steak and seared tuna. If you haven't had it yet, we highly recommend you try it if ever given the chance - it's legal in some countries, including Japan, Norway, Iceland, and the Arctic, where whale hunting is strictly regulated.