Yarra Pygmy Perch

Interesting Info

• The Yarra Pygmy Perch is a tiny freshwater fish found only in southeastern Australia, mainly in coastal drainages of western Victoria and southeastern South Australia.
• They have a short, deep body coloured olive-brown to golden, with darker blotches along the sides. Unlike the Southern Pygmy Perch, they lack bright breeding colours, which is why they were given the name obscura (meaning “hidden” or “plain”).
• Adults are usually just 3–4 cm (1.2–1.6 in) long, with the largest reaching 6 cm (2.3 in) — making them one of the smallest freshwater fish in Australia.
• Yarra Pygmy Perch live in shallow, slow-flowing streams, wetlands, and billabongs, especially where there is dense vegetation. They rarely venture into open water.
• They are omnivores, eating tiny aquatic invertebrates, insect larvae, and small amounts of algae.
• Once widespread in Victoria’s Yarra and other river systems, their range has dramatically shrunk over the last century due to habitat loss, river regulation, and predation by invasive fish like redfin and gambusia.
• They are often preyed upon by larger fish, such as introduced trout species, as well as birds and other predators.
• Today, most populations are small, isolated, and fragmented, making them highly vulnerable to drought and climate change.
• Breeding happens in spring and early summer (October–December), triggered by rising water temperatures. Females lay clusters of adhesive eggs on aquatic plants or submerged logs. Males guard the eggs until they hatch, usually within a week.
• Lifespan is short, usually 1–3 years, which makes populations sensitive to sudden changes in habitat.