The Barramundi Fish grows up as a male and after at least one spawning season turns into a female for breeding.
The barramundi or Asian sea bass is a species of catadromous fish in the family Latidae of the order Perciformes. The species is widely distributed in the Indo-West Pacific region from South 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".
This species has an elongated body form with a large, slightly oblique mouth and an upper jaw extending behind the eye. The barramundi feeds on crustaceans, mollusks, and smaller fish (including its own species); juveniles feed on zooplankton. It inhabits rivers and descends to estuaries and tidal flats to spawn. In areas remote from freshwater, purely marine populations may become established.
At the start of the monsoon, males migrate downriver to meet females, which lay very large numbers of eggs (several million 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 protogyny and some males do not undergo sexual inversion.