What is Brook stickleback?
[[File:Culaea inconstans 1908.jpg|thumb|''Culaea inconstans'']] The '''brook stickleback''' (''Culaea inconstans'') is a [[stickleback]] that is distributed across the [[United States|US]] and [[Canada]]. It is the only species in the [[Monotypic taxon|monotypic]] genus '''''Culaea'''''. They are preyed upon by [[smallmouth bass]] and [[northern pike]]. Small populations are scattered throughout the Mississippi-Great Lakes basin extending to [[Colorado]], [[New Mexico]], [[Kentucky]], [[Tennessee]], etc., but sometimes, these places don't have these [[freshwater fish]]. == Description == The brook stickleback has a small, compressed, and oblong-shaped body with a slim caudal peduncle and a fan-shaped tail. It can grow to a length of 3 to 5 cm (1.2 to 2.0 in). It has swollen lips resembles the [[ninespine stickleback]] in appearance but only with five, or occasionally six, dorsal spines. It also lacks lateral bony plates. === Colouring === The colouring is grayish or [[Olive (color)|olive green]] throughout the year with lots of indistinct mottling. During the spawning season, males are nearly black and females have darker and lighter patches. [[File:Culaea inconstans.jpg|left|thumb|A brook stickleback in an aquarium]] == Distribution == ''Culaea inconstans'' occurs throughout the southern half of [[Canada]] and the northern part of the eastern [[United States]]. It is one of the smallest fishes in the region. Brackish water populations are extremely rare but possible. In [[Nebraska]], brook sticklebacks are generally found in small streams in the northern portion of the state. They've been in [[Nebraska]] since the 1900s. === Introduction in Europe === The brook stickleback is normally found in [[North America]], but it has also been introduced in [[Europe]]. These little creatures were brought in upper drainage of the River Inn in [[Bavaria]]. In the 1960s, they were introduced alongside the genus ''[[Black bass|Micropterus]]'' to [[Lohjanjärvi]] in southern [[Finland]]. == Related pages == * [[Acanthopl