Western Mud Minnow
The Mud Minnow (Galaxiella munda) is a small freshwater fish which grows to a maximum length of 58 mm and has a scaleless, elongated body and long straight gut. Adults are brown-grey on their back with a white belly and possess several whitish blotches near their top midline. They also possess a broad brown stripe just below their midline from behind the eye to the base of their tail fin.
Habitat and Life Cycle
The Mud Minnow is a carnivorous species feeding on insects and their larvae in water, and also on micro-crustaceans. The Mud Minnow feeds near the fringe of streams and pools and is typically found near submerged vegetation, occasionally in the still water of ponds, swamps and roadside drains, and often inhabiting darkly tannin-stained and acidic water. The water where the Mud Minnow is found exhibits marked seasonal temperature fluctuations.
The Mud Minnow is known to occur in the south western corner of Australia extending from Margaret River in the west to Two Peoples Bay (near Albany) in the east, with an isolated population occurring approximately 100 km north of Perth near Gingin. The Mud Minnow has also recently been found at one location on the Vasse River, near Busselton, within 50 km and north of the Margaret River.
The mud minnow is listed by the state as ‘vulnerable’ however is not federally listed.
A number of threats to the survival of the Mud Minnow have been proposed including: competition and predation from introduced fish (e.g. Redfin Perch, Mosquitofish and Trout); the species’ low tolerance to salinity and increasing salinisation of freshwater streams and increased water extraction. The Mud Minnow may also be affected by river regulation (e.g. weir and dam construction) and the subsequent infestation (or stocking) of these areas with predatory fish species.
Western Mud Minnow and Climate Change
SWCC Strategic Priority
The Western Mud Minnow is identified as a second order priority asset within SWCC’s NRM Strategy under the Aquatic Biodiversity theme.