Central Mudminnow (Umbra limi) - Introduced

A typical mud-brown-colored 4-inch central mudminnow.

Identification. Adults thick-bodied, subadults more streamlined. Blunt snout. Sides mottled or with faint vertical bars. Tail fin rounded and usually preceded by a dark vertical bar. Around 13-14 soft dorsal rays. Soft anal rays around 11. Typically dark brown to olive on back, lighter brown on sides.

This 3-inch subadult central mudminnow is much more brightly colored than the larger adults. The dark vertical bar preceding the tail fin is very evident in this photo.

Size. Commonly 2 to 3 inches. State survey max. size 4.3 inches. Max. reported size 5.5 inches.

Distribution. Native to the Great Lakes region, primarily within the United States. In Connecticut, they are primarily restricted to backwater areas of the Connecticut River and in the lower ends of some of its tributary streams. They are also found in areas of the Connecticut River in Massachusetts. The central mudminnow was first reported in Connecticut in 1980. A population of unknown origin was recently (2005) discovered in Black Pond (Meriden).

All maps created in 2009. See CT DEEP Fish Community Data for updated distributions.

Habits. Prefer heavily vegetated areas and mud bottoms of sloughs and swamps. Mudminnows can tolerate very low dissolved-oxygen levels and high water temperatures. Can be captured with small-mesh dip nets and seines.

Comments. Mudminnows have a modified swim bladder that allows them to breathe by gulping air at the surface of the water. 

Although central mudminnows look superficially like minnows or killifish, they are actually more closely related to pickerel and pike.

Text and images adapted from Jacobs, R. P., O'Donnell, E. B., and Connecticut DEEP. (2009). A Pictorial Guide to Freshwater Fishes of Connecticut. Hartford, CT. Available for purchase at the DEEP Store.