Brown bullheads were introduced in the 1920s, which makes them relatively new inhabitants of Finnish waters. Plantings were justified on the grounds of good taste. It originates in North America. Nowadays they reside in the lakes and streams of Southern Finland, as well as in coastal bays. They can weigh up to one kilogram and grow up to forty centimetres in length.
Brown bullhead spends their days lurking amidst rocks while waiting for twilight to fall, at which point they go looking for food. As prey they seek insects, worms and crustaceans, which they locate using their barbells and their extraordinary sense of hearing. Brown bullheads have four barbells on both their upper and lower jaws. They have yellowish-brown scaleless skin with an adipose fin on their back.