Also known as Opah, Moonfish is a stunning looking fish - round, with a thin body like Pomfret, with striking blue and pink skin with red fins. It can grow up to 100kg, living at depths of 100-400m in most warm waters, and can swim up as far as the UK in summer. Under the skin, there is firm, salmon-like flesh, which is very highly rated. Best filleted, portioned and pan-fried. Now easier to obtain, but never confuse Moonfish with Sunfish (Mola mola) - which has a stubby, flipper-like tail, dark brown leathery skin, and should be avoided like the plague.