The brown bullhead (Ameiurus nebulosus) is a fish of the family Ictaluridae that is widely distributed in North America.

[9] Juvenile brown bullheads are similar in appearance, but are more likely to be of a single solid color.

These locations include Georgia, Alabama, Arizona, Arkansas, California, Colorado, Hawaii, Idaho, Kansas, Kentucky, Louisiana, Maine, Missouri, Nebraska, Nevada, New Hampshire, New Mexico, Ohio, Oklahoma, Oregon, Virginia, and Washington.

[8] The brown bullhead thrives in a variety of habitats, including lakes, ponds, and slow-moving streams with low oxygen or muddy conditions.

They are scarce during the day, but come out at night to feed, searching the bottom of a lake or river for food.

Brown bullheads can withstand a wide range of water temperatures and low oxygen levels.

Brown bullheads can survive waters with heavy pollution and dissolved oxygen values as low as 0.2 ppm.

[8] Because of bullheads' tolerance of low oxygen levels, they are less threatened by winterkill and are capable of surviving in relatively extreme environments.

When caught in very clear water when the flesh is firm and reddish to pinkish, the hornpout is quite edible and delicious.

The females lay eggs in dark locations such as under rocks and inside logs,[16] where they are externally fertilized by the male.

[17] The fish has been introduced into many European countries, such as Poland, Germany, Sweden, Norway, Finland, Romania, Estonia, Hungary, Serbia, and Croatia.

Brown bullheads have also been introduced to western North America, Chile, Puerto Rico and New Zealand.

[18] Countries who have reported adverse effects from the introduction of the brown bullhead species include Iran and Turkey.

They are prey to the following species: northern pike, muskellunge, walleye, snapping turtles, water snakes, green herons, yellow perch, and sunfish.

[14] As a mode of physical defense against predators, bullhead species have a sharp spine on the leading edge of their dorsal and pectoral fins.

[8] Brown bullheads can tolerate very low dissolved oxygen levels that result from industrial and domestic pollution, aiding in their overall high rate of survivorship.