Western Population of Olive Perchlet

Scientific nameHow to identify an Olive Perchlet

Ambassis agassizii

Status in NSW

Endangered population

Characteristics

The Olive Perchlet has an oval shaped body. Other characteristics include:

  1. Large eyes
  2. Semi-transparent body with dark-edged scales
  3. Clear fins
  4. A single dorsal fin with a deep knotch
  5. Forked tail

Size

It can grow to about 70-80 mm but more commonly seen at less than 60 mm.

Distribution

Olive Perchlets are a small native fish that occur in both eastern (coastal) and western (Murray-Darling) drainages, but these populations may be genetically distinct. The western population of the Olive Perchlet was once widespread throughout the Murray-Darling system of South Australia, Victoria, western New South Wales and southern Queensland. This population has suffered a serious decline and is now found only at a few sites in the Darling River drainage.


Habitat

The Olive Perchlet inhabits rivers, creeks, ponds and swamps with slow flowing or still waters. They are usually found in sheltered areas such as overhanging vegetation, aquatic macrophyte beds, logs, dead branches and boulders during the day, and disperse to feed during the night.

Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat
Olive Perchlet habitat

Why is the Western population of Olive Perchlet threatened?

  • Predation by introduced fish species such as Gambusia (Gambusia holbrooki) and Redfin Perch (Perca fluviatilis);
  • Habitat degradation, including the removal of vegetation, logs and snags;
  • Rapid fluctuations in water levels as a result of river regulation resulting in negative impacts on reproduction and recruitment;
  • Spawning failures due to cold water releases from dams (temperature pollution);
  • Loss of instream aquatic vegetation through the impacts of river regulation and carp (Cyprinus carpio).

Olive Perchlet stocking into the Gwydir Valley (Photo: L. Tosetto)

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