The Australian blacktip shark is known to form large groups, segregated by size and sex. It preys mainly on teleost fishes, including ponyfishes, grunters, tunas, and herring. Cephalopods are a secondary food source, which are particularly important around April. This species also occasionally consumes smaller sharks, including snaggletooth sharks ("Hemipristis pristis"), spottail sharks ("C. sorrah"), and sharpnose sharks ("Rhizoprionodon"). Their diets shift with age: smaller individuals feed on proportionately more bottom-dwelling fish, while larger individuals feed on proportionately more midwater fish and cephalopods. Documented parasites of this shark include the tapeworms "Fossobothrium perplexum" and "Platybothrium" sp., and the copepod "Perissopus dentatus".