The black mudfish (Neochanna diversus) is a fish of the family Galaxiidae, found only in swamps and wetlands in the northern half of the North Island of New Zealand, from Kaitaia in the north to the Mokau River in the south. An 85-90% loss of wetlands has occurred, especially from Waikato and Hauraki Plains. The most significant threat is wetland drainage, and this has slowed so the decline has stabilized; other threats include mosquitofish (which eat juveniles and compete with adults), pollution, sedimentation, and fires.