Blue Mountains Perch

Interesting Info

• The Blue Mountains Perch is a newly recognised freshwater fish from the Hawkesbury–Nepean and Shoalhaven River systems in New South Wales.
• For years it was thought to be a population of the Macquarie Perch (Macquaria australasica), but new research has shown it is genetically and morphologically distinct — making it a separate species.
• Their distribution is limited to the Blue Mountains and surrounding catchments, making them far less widespread than Macquarie Perch.
• They are slim-bodied and deep-flanked, with a silvery-grey to dark olive colour, often with faint mottling along the sides.
• Their fins are slightly darker, and compared to Macquarie Perch, they often show subtle differences in head shape and scale patterns.
• They live in upland and midland rivers, preferring shaded pools, rocky runs, and undercut banks with good cover from logs and boulders.
• Juveniles feed mainly on insect larvae and small crustaceans, while adults eat a wider mix including aquatic insects, molluscs, and small fish.
• Breeding occurs in spring to early summer (October–December) when water temperatures rise above 16°C. Like Macquarie Perch, they are egg scatterers, releasing eggs over gravel and rocky substrates.
• Because they have only recently been recognised as distinct, little is known about their detailed ecology — but it’s likely they play a similar role as mid-level predators and insect controllers in upland streams.
• Historically, they were sometimes caught by anglers as “perch,” but are now recognised as a species of high conservation concern.
• Lifespan is thought to be 10–15 years, similar to their close relatives.