sits on every silty river bottom found

Size
Length: 8–12 cm, Weight: 10–20 g
Lifespan
3–5 years
Diet
Feeds on aquatic insects small crustaceans and insect larvae. Found in almost every lake river and swampy drain from coast to sub-alpine regions nationwide.
Habitat
Inhabits almost every lake river and swampy drain from coast to sub-alpine regions. Sits on sandy or silty bottom pretending to be stone. Ultimate everyman of New Zealand waters.
Range
Found throughout North and South Islands in almost every lake river and swampy drain. Most common in lowland waterways with sandy or silty bottoms across diverse freshwater environments.
Endemism
Endemic
Main Threats
No significant natural threats. Species is widespread and common. Habitat loss from stream modification and drainage. Predation by introduced trout also impacts local populations in degraded waterways.
Population
Not Threatened. One of most widespread and common native fish. Hardy survivor that persists even in degraded habitats. Part of uniquely Kiwi family of bullies that have mastered art of staying put.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
native freshwater bully, observe from bank to avoid disturbance
Conservation Note
Endemic freshwater fish; widespread in streams and rivers throughout New Zealand.
Assessment
NZTCS Freshwater Fishes (2023)
Te Ao Māori
The Common Bully is the background character of the Kiwi childhood. If you have ever spent a summer afternoon catching tiddlers in a glass jar at the edge of a lake you were hunting the bully. In Māori tradition they were not the stars like the tuna (eel). But they were a reliable food source. Often caught in fine-meshed nets along with whitebait. They represent the unseen majority. The quiet stubborn residents who do not make the headlines. But keep the ecosystem's engine running. This cultural recognition highlights their ubiquity. And their foundational role.
The grumpy old man of the lakebed. Growing up to 15 centimetres common bullies are thick-set blunt-headed fish. They have large fan-like pectoral fins. These are used to prop themselves up on the bottom. They do not really swim so much as hop across the sand in short jerky bursts. The colour is a masterclass in camouflage. Splotchy browns olives and greys make them invisible the moment they stop moving. If you see a small shape dart away from your foot in the shallows and then vanish into the silt you have just been bullied. The reaction is instinctive. The disappearance is total. Incredibly adaptable defines this species. Some populations spend their whole lives in landlocked lakes. Others are diadromous. They hatch in rivers. They wash out to sea as larvae. Then they climb back into freshwater as whitebait-sized juveniles. Surprisingly territorial for such small fish. A male bully stakes out a flat rock or a sunken log. He defends it with comical aggression against any interloper. During breeding season males turn much darker. Almost black. This is to impress females. The female lays eggs in a neat single layer under a rock. The male stays behind as a bodyguard. He fans the eggs with his fins. This keeps them clean until they hatch. The dedication is notable. The effort is constant. The protein bar of the New Zealand waterway describes their ecological role. Common bullies are the primary food source for almost everything else. Trout eels and shags all rely on them to stay fat and happy. Without them the entire freshwater food chain would collapse. They are the quiet camouflaged foundation of our rivers. The fish that stays behind when the flashier migrants head to the sea. The contribution is vital. The recognition is low. The survival is essential. To find a healthy population of bullies is to find a river that still has its soul intact. Even if that soul is a bit small. A bit brown. And very grumpy about you stepping near its rock. This is the background character of the Kiwi childhood. If you have ever spent a summer afternoon catching tiddlers in a glass jar at the edge of a lake you were hunting the bully. The memory is universal. The catch was easy. The release was optional. The experience was formative. It carries on in the shallows. Unseen by the casual observer. But prized by those who know. It remains on the sand. A testament to the intact river. A relic of the wild drain. It waits for the predator. Or it does not. The choice is ecological. The outcome is certain. The fish persists. It moves through the water. Unaware of the name. Unconcerned with the status. Focused on survival. And the next meal. In the murky shallow expanse. Where it belongs. The common bully endures. A symbol of the persistent native. A staple of the local diet. It carries on.