The barramundi, commonly known as the Giant Perch, is a fish that is rarely seen in aquariums, most likely due to its massive adult size. Barramundi can grow to be more than a meter long and must be housed in extremely large aquariums. Individual fish can double in size over the first 6-12 months of their lives, depending on their food. An intriguing fact: All Barramundi are born male. They begin their lives in freshwater, where they stay until sexual maturity.They move downstream to the river’s mouth, where they join the females to spawn. The ladies are older fish that transitioned from male to female during one of the previous breeding seasons. Barramundi spawn in saltwater, and some return to the river (males), while others remain in the ocean to become females.