Search Field Guide
Advanced Search
Montana Animal Field Guide

Montana Field Guides

Brook Stickleback - Culaea inconstans

Potential Species of Concern

Global Rank: G5
State Rank: S4

Agency Status


External Links

General Description
The brook stickleback is unique among Montana's fishes in its appearance. This species is native east of the Continental Divide in northeastern Montana. Sticklebacks live in slow streams and lakes with submerged plants. They are spring spawners that build a nest from pieces of vegetation they glue together with a special kidney secretion. Sticklebacks feed on small crustaceans and insects and can reach a length of about 3 inches. They provide some food for other predatory fishes.

Diagnostic Characteristics
Brook sticklebacks are olive-green with mottling or light spots on the sides; the undersides are light yellow to silver. During breeding season the males are black with tinges of red; females may be dusky. The body is smooth, without scales, but with minute bony plates about the pores on the lateral line.

Species Range
Montana Range

Click the legend blocks above to view individual ranges.

Western Hemisphere Range


Summary of Observations Submitted for Montana
Number of Observations: 755

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Brook sticklebacks are associated with dense vegetation in slow, clear streams and shallow lakes.

Food Habits
This species feeds on almost any aquatic invertebrate that is available. Scuds, water fleas, midges, and very small fishes have been found in their stomachs.

Reproductive Characteristics
Brook sticklebacks spawn May through June. The male builds a nest from vegetation and lures one or more females in to deposit eggs. Incubation is for 8 days at 60 degrees F.

Login Logout
Citation for data on this website:
Brook Stickleback — Culaea inconstans.  Montana Field Guide.  .  Retrieved on , from