The red morwong, Cheilodactylus fuscus, is a large and conspicuous temperate reef fish of south-eastern Australia and is a popular target of spearfishers as well as an indicator species of bioaccumulation for water quality authorities. C. fuscus is a benthic carnivore, feeding on crustaceans, polychaetes and molluscs. Amphipods and other small benthic crustaceans (tanaids, cladocerans, cumaceans and mysids) constitute over 60% of the diet of juvenile fish (<200 mm standard length, SL), but only 35% of the adult diet (200 to 390 mm SL), and <20% of large adult diet (360 to 500 mm SL, which were obtained from spearfishing competitions). Adult and large adult fish consume significantly greater proportions of brachyurans, molluscs and echinoderms than juveniles. Juveniles occur over turfing algae in the upper sub-tidal region to depths of five metres, and feed continuously throughout the day, with bite rates of up to 16 per minute and high gut fullness (60-100%) throughout the day. Conversely, adults occur in deeper sub-tidal habitats (between five and 18 metres), rarely feed during the day (<4 bites per minute) and adult gut fullness declines from >50% in the early morning to <18% by early afternoon. Ontogenetic and diel factors as well as habitat choice influence the diet of this cheilodactylid. The crepuscular nature of feeding in adults of this species is in contrast to several other cheilodactylids which feed during the day.