Aquatic insects form the bulk of its diet. Terrestrial items falling into water are taken opportunistically. Small crustaceans supplement intake during certain seasons. It feeds primarily on drifting prey caught in current or picked from substrate surfaces in shaded swamp sections. The brown mudfish is not actually a fish that lives in mud. It lives in water above mud. But when that water disappears, it survives by burrowing into moist substrate and entering a dormant state. This ability to withstand drought makes the brown mudfish uniquely adapted to New Zealand's ephemeral wetlands. It can survive months without surface water, waiting for rain to refill its habitat. Kōwaro. The Māori name refers to several mudfish species. Early Māori valued mudfish as a food source, particularly during winter months when other fish were less available. They were caught by hand in swamps or using simple traps. The flesh was described as sweet and nutritious. Settlers also consumed mudfish, though they found the preparation laborious compared to more conventional fish species. The brown mudfish reaches about 150 millimetres in length. Its body is cylindrical and elongated, coloured brown with irregular darker markings. It lacks pelvic fins, giving it a snake-like appearance when moving through dense vegetation. This streamlined shape allows it to navigate through thick swamp plants and burrow into mud when necessary. Spawning occurs in spring and summer. Eggs are laid amongst submerged vegetation in shallow water. The larvae hatch and remain in freshwater, completing their entire life cycle without ever reaching the sea. This non-diadromous strategy means the species is entirely dependent on maintaining suitable wetland habitat. There is no marine phase to provide refuge if swamps dry permanently. Threats come primarily from habitat loss. Wetland drainage for agriculture has destroyed much of the brown mudfish's historic range. Remaining populations persist in protected swamps and undeveloped wetlands. Introduced predators such as trout do not typically inhabit swamp environments, providing some natural protection. However, habitat fragmentation isolates populations and reduces genetic diversity. Climate change may alter rainfall patterns, affecting the frequency and duration of drought periods that mudfish rely on for survival. The brown mudfish is classified as Not Threatened. It remains widespread throughout the North Island and northern South Island. Populations are stable in suitable wetland habitat. Conservation efforts focus on protecting remaining wetlands from drainage and development. The species serves as an indicator of wetland health. Its presence signals intact hydrological regimes and suitable vegetation structure. Where mudfish thrive, other wetland species likely persist as well.