Red emperors live in a variety of habitats including coral reef lagoons, reefs, sand flats and gravel patches. Small juveniles frequently form commensal associations with sea-urchins. Juveniles less than 20cm long are common in nearshore turbid waters, in mangrove areas or among both coast and deeper water offshore reefs. Red emperors move to deeper water as they grow larger, with large fish often moving into shallower water during the winter months.
Red emperors form schools of similar-sized individual or are solitary.
Red Emperors on the Great Barrier Reef are estimated to be 20-21 cm fork length at 1 year of age and 40cm at 3 years of age. Red emperors reach a maximum total length of at least 100 cm, possibly 116cm fork length and live to at least 10 years of age. Red Emperor are caught commercially by demersal and semi-pelagic otter trawls, traps, droplines and deepwater handlines. They are also longlined in Queensland. The fisheries operate all year.