Freshwater Tongue Sole

Interesting Info

• The freshwater tongue sole is found across northern Queensland, the Northern Territory, and northern Western Australia, especially in slow-flowing rivers and floodplain lagoons.
• It also has a wide Indo-Pacific distribution, including Southeast Asia, Papua New Guinea, and the Pacific islands.
• Its body is long and narrow, with both eyes on the right side of its head — a classic feature of flatfishes.
• The upper side is brown to grey with fine mottling, while the underside is pale, helping it blend into sandy or muddy river bottoms.
• Unlike most soles, which are marine, this species is found in freshwater rivers and billabongs, sometimes far from the coast.
• Their diet consists of small invertebrates such as insect larvae, worms, and tiny crustaceans sifted from the mud and sand.
• They prefer quiet backwaters, sandy shallows, and muddy floodplain lagoons, where their camouflage makes them nearly invisible.
• During the wet season they may move into newly flooded wetlands, feeding in shallow water rich in insects and crustaceans.
• Breeding is believed to occur in freshwater during the wet season, when females release eggs that drift in open water before hatching into planktonic larvae.
• Young fish eventually settle to the bottom, where they adopt the flattened, camouflaged body shape of adults.
• They are rarely seen because of their excellent camouflage and habit of lying flat against the bottom.
• The lifespan is not well studied but is thought to be 3–5 years, similar to other small flatfish.