The barramundi or Asian sea bass (Lates calcarifer) is a species of catedromous fish in the family Latidae of order Perciformes. The species is widely distributed in the Indo-West Pacific region from Southeast Asia to Papua New Guinea and Northern Australia.
Barramundi is a loanword from an Australian Aboriginal language of the Rockhampton area in Queensland meaning ‘large-scaled river fish’.
They have large, silver scales, which may become darker or lighter, depending on their environments. Their bodies can reach up to 1.8 m (5.9 ft) long, though evidence of them being caught at this size is scarce.
Barramundi are demersal, inhabiting coastal waters, estuaries, lagoons, and rivers; they are found in clear to turbid water, usually within a temperature range of 26−30 °C. This species does not undertake extensive migrations within or between river systems, which has presumably influenced establishment of genetically distinct stocks in Northern Australia.
The barramundi feeds on crustaceans, molluscs and smaller fish (including its own species); juveniles feed on zooplankton. In the impoundment environment at Lake Proserpine, Barra tend to feed on bony bream and red claw.
The barramundi is euryhaline, but stenothermal. It inhabits rivers and descends to estuaries and tidal flats to spawn. In areas remote from fresh water, purely marine populations may become established.
At the start of the monson, males migrate downriver to meet females, which lay very large numbers of eggs (several millions each). The adults do not guard the eggs or the fry, which require brackish water to develop.
The species is sequentially hermaphroditic with most individuals maturing as males and becoming female after at least one spawning season; most of the larger specimens are therefore female. Fish held in captivity sometimes demonstrate features atypical of fish in the wild: they change sex at a smaller size, exhibit a higher proportion of protandry and some males do not undergo sexual inversion (which is kind of cool and a little bit freaky at the same time.)
Juveniles are a popular aquarium fish, and can be very entertaining, especially at feeding time. However, they grow quickly, so they are recommended to be kept in setups of 500 litres or larger. In aquaria, they become quite tame and can be hand fed; they are not aggressive, but their feeding reflex is violent and sudden, so they can not be kept with any tank mates small enough to be swallowed.