Brook stickleback

The brook stickleback (Culaea inconstans) is a stickleback that is distributed across the US and Canada. It is the only species in the monotypic genus Culaea. They are preyed upon by smallmouth bass and northern pike.

Culaea inconstans

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 green throughout the year with lots of indistinct mottling. During the spawning season, males are nearly black and females have darker and lighter patches.

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 Micropterus to Lohjanjärvi in southern Finland.

Related pages

• Acanthopleurus
• Boulder
• Eschmeyer nexus
• Stickleback
• Three-spined stickleback

Range map of the brook stickleback

References

1. Froese, Rainer; Pauly, Daniel (eds.) (2012). "Culaea inconstans" in FishBase. October 2012 version.
2. "Brook stickleback: Culaea inconstans". NatureGate. Retrieved 15 December 2013.
3. NatureServe (2013). "Culaea inconstans". IUCN Red List of Threatened Species. Retrieved 27 November 2022.
4. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Culaea". Catalog of Fishes. California Academy of Sciences. Retrieved 27 November 2022.