Introduced trout pose the primary threat to survival. Brown trout and rainbow trout compete for food and space while preying on juveniles and adults. Habitat degradation from forestry and agriculture compounds pressure on remaining populations. Riparian clearing removes essential cover. Dina's bully inhabits lowland streams and wetlands across the northern North Island. These waters flow slowly through pastoral land or native bush, bordered by dense vegetation that provides essential cover. Submerged plants offer hiding places from predators and spawning sites during spring months. Without this vegetation, the fish becomes visible to everything that hunts it. Named for Dina, this species reaches about 90 millimetres in length. Its body is slender, coloured pale brown with irregular darker markings along the sides. Large pectoral fins allow it to navigate through dense aquatic vegetation. During breeding season, males develop darker colouration and guard nests under flat stones or amongst plant roots. Spawning occurs in spring. Eggs are laid amongst fine roots and submerged vegetation in shallow water. The male guards the eggs, fanning them to keep oxygenated. The larvae hatch and remain in freshwater, never migrating to sea. This non-diadromous life history means the species is entirely dependent on maintaining suitable freshwater habitat year-round. Diet consists of aquatic insects and small crustaceans. The fish feeds on drifting prey caught in current or picked from plant surfaces. It is active during daylight hours, visible in clear water to researchers monitoring populations and predators hunting meals. Classified as Nationally Vulnerable, Dina's bully faces threats from multiple directions. Habitat loss through wetland drainage and stream modification removes the cover the fish needs. Introduced trout patrol the same waters, eating juvenile and adult bullies alike. Sediment from agricultural runoff smothers spawning vegetation. Water extraction reduces flows, concentrating predators and raising temperatures beyond tolerable limits. Each threat compounds the others. The Dina's bully persists in shrinking pockets of suitable habitat, clinging to existence in streams that farmers drain and developers modify. Conservation efforts focus on protecting remaining populations through riparian planting, trout exclusion, and habitat restoration.