upper part of the body is olive-brown in color, mottled throughout, with up to 14 indistinct brown vertical bars on the sides and a prominent dark verticle bar located at the base of the tail, belly is yellow to white and fins are brownish, large scales, can tolerate low oxygen levels
scattered throughout eastern and northcentral Iowa and at one location in northwest Iowa, found in streams, sloughs, ponds, lakes, and marshes
quatic and terrestrial arthropods, snails, fish, plants, and algae
The central mudminnow is scattered throughout eastern and northcentral Iowa and was recently documented at one location in northwest Iowa. This species occurs in moderate to densely vegetated streams, sloughs, ponds, lakes and marshes. It avoids fast-moving waters. They are a hardy fish and found in areas where the oxygen concentration often reaches very low levels. Drainage of Iowa wetlands over the last four decade has eliminated suitable habitats in much of its original range.
The central mudminnow is a robust-bodied, mottled fish with a short, blunt snout, a short dorsal fin located posteriority, and large scales over the head and body. The upper part of the body is olive-brown in color, mottled throughout, with up to l4 indistinct dark brown vertical bars on the sides, and a prominent dark vertical bar located at the base of the tail. The belly is yellow to white, and the fins are brownish. The mouth is terminal with a slightly protruding lower jaw. Gill rakers are short and stout, numbering l3 to l5. The dorsal fin has l3 to l5 soft rays, pelvic fin rays number 6 to 7, pectoral fin rays l4 to l6, anal fin rays 7 to 9, and all of the fins are rounded on the edges. It reaches a maximum length of 5 to 6 inches, with an average length of about 2 inches or slightly larger.
Spawning begins in April at water temperatures ranging from 55 to 60 degrees F. Shallow backwater areas subject to overflow provide excellent breeding grounds, with a rise in water temperature providing the stimuli for spawning. The female deposits the adhesive eggs singly and directly in aquatic vegetation. Egg production is from 200 to 2,200, depending upon body size. The eggs hatch in about seven days.
Scales of the mudminnow do not show growth annuli; age is determined by viewing otoliths or estimated from length-frequency distribution. Life span of the mudminnow is quite long; some fish up to 9 years of age have been taken. Food is collected mostly from the bottom, with aquatic and terrestrial arthropods, snails, fish, plants and algae making up their diet.
The mudminnow is difficult to sample because it flees into bottom sediments when a small seine approaches, but once the water is stirred up and turbid, it can be easily captured. The mudminnow has both gas-absorbing and secreting organs in the swim bladder. When oxygen levels are insufficient in the water, it simply gulps air from the surface.
The central mudminnow is used extensively as a bait minnow where it is plentiful. Many walleye anglers prefer it for bait because of its hardiness.