The sculpins are about 300 species of small, rather grotesquely shaped fish that make up the family Cottidae. Most species of sculpins occur in cold or cool-temperate marine waters of the Northern Hemisphere, but a few species occur in fresh waters of northern Asia, Europe, and North America.
Sculpins are short, stout-bodied fishes, with a large and broad head, large eyes, a large mouth, and broad, coarsely veined fins. Sculpins are bottom-dwelling fishes, feeding voraciously on diverse types of aquatic invertebrates and plant matter. Sculpins do not have typical scales covering their body, but are coated by a slimy mucus, with numerous tubercles or prickles that give these fish a rough feel when handled.
Most species of sculpin occur in northern marine waters. The sea raven (Hemitripterus americanus) occurs on continental-shelf waters of the northeastern Atlantic Ocean, from New England to Labrador. This is a relatively large species of sculpin, attaining a weight as much as 6.5 lb (3 kg). When they are captured, sea ravens will quickly swallow water and air to distend their body, presumably hoping to make it more difficult to be swallowed whole by a predator.
The grubby (Myoxocephalus aenaeus) is a smaller species of the northeastern Atlantic, sometimes considered a nuisance by human fishers because when this fish is abundant it takes baited hooks set for other species.
Several species of sculpins occur in fresh waters in North America. The slimy sculpin (Cottus cognatus) is a 5-8-cm-long species that is very widespread in boreal and temperate regions of the continent. The similar-sized, mottled sculpin (Cottus bairdi) is widespread in northeastern regions. The deepwater sculpin (Myoxocephalus quadricornis) is a relatively large species, attaining a length of up to 8.4 in (21 cm), and occurring in deeper waters of the Great Lakes and some other large lakes.