Common bully

The common bully (Gobiomorphus cotidianus), or toitoi (Māori), is a fish endemic to New Zealand, and is present throughout the country. There are three other bully species that can be confused with common bullies. There are few characteristics of the common bully that separate it from other species. Vertical lines present on the cheek are a good defining characteristic, along with the location of head pores and scale patterns on the head although these are hard to establish when seen in the wild. It is an amphidromous fish meaning it is able to survive in marine and fresh water environments. It is a small fish only growing as big as 15 cm. It can live in marine, fresh water or brackish water habitats and generally lives in benthic zones. Some populations venture into the sea and occur in coastal rivers and streams while other land-locked populations have established in many shallow mainland lakes. They generally prefer moderate to slow moving water which means they are the most likely bully species to be sighted. Its diet consists mainly of small benthic invertebrates but also involves insect larvae and crustacea.