Orange roughy (Hoplostethus atlanticus) is a deep-sea whitefish landed from cold waters hundreds of metres down, prized for its firm, pearly-white flesh and a mild, faintly sweet flavour that holds together in large moist flakes. Sold almost entirely as skinless boneless fillets, it became a supermarket staple in the 1980s as a clean, versatile substitute for cod, sole and other white fish.