Buffalo fish, members of the genus Ictiobus, are large freshwater fish native to North America. They are often encountered in rivers, lakes, and impoundments across the United States, Canada, Mexico, and Guatemala. While sometimes mistaken for carp due to their general appearance, buffalo fish are distinct species belonging to the sucker family, Catostomidae. This article explores their physical characteristics, including overall body shape, key identifying features, and species variations.
Overall Body Shape and Size
Buffalo fish possess a robust and deep-bodied structure, typically appearing somewhat compressed from side to side. Their overall profile often features an arched back. These fish are generally large, with most species commonly reaching lengths of 20 to 30 inches. Some individuals can grow significantly larger, with documented lengths up to 4 feet.
The weight of buffalo fish varies with size and species. Typical adult specimens often weigh between 10 to 30 pounds. Some larger individuals, particularly the Bigmouth Buffalo, can reach weights exceeding 80 pounds. Their considerable size and sturdy build contribute to their notable presence in freshwater ecosystems.
Key Identifying Features
A distinguishing feature of buffalo fish is their mouth structure, which is typically subterminal, meaning it points downward. This mouth is also protractile, allowing it to extend forward, an adaptation for bottom feeding. Unlike common carp, buffalo fish notably lack barbels, which are the whisker-like appendages found around the mouths of carp. This absence is a primary visual cue for differentiation.
Their bodies are covered in large, cycloid scales, which are smooth to the touch. The dorsal fin is long and single, often described as angular or sickle-shaped, extending relatively far back on the body. The caudal, or tail, fin is typically large and distinctly forked. Pectoral and pelvic fins are also present, contributing to their maneuverability in water.
Buffalo fish generally exhibit coloration ranging from dark olive to brownish or bronze on their upper bodies and sides. This darker shade gradually fades to lighter hues, such as silvery or yellowish, on their bellies. Their eyes are relatively small in proportion to their large heads.
Variations Among Buffalo Fish Species
The term “buffalo fish” encompasses several distinct species within the Ictiobus genus. The three most commonly recognized North American species are the Bigmouth Buffalo (Ictiobus cyprinellus), Smallmouth Buffalo (Ictiobus bubalus), and Black Buffalo (Ictiobus niger). These species can be differentiated primarily by their mouth characteristics and body profiles.
The Bigmouth Buffalo is distinguished by its large, oblique, and terminal mouth, meaning it opens forward or slightly upward. This species typically has a less pronounced hump on its back compared to its relatives. Its coloration often ranges from brownish olive to green-gold, sometimes with coppery reflections.
In contrast, the Smallmouth Buffalo features a distinctly smaller, subterminal mouth that points downward. This species commonly exhibits a more pronounced humpback profile, giving it a deeper body. Its coloration tends to be darker, including shades of light brown, gray, bronze, or coppery-green on its back and sides.
The Black Buffalo typically has a very small, subterminal mouth that is nearly horizontal, with thicker, grooved lips. Its body is often described as the stoutest or most cylindrical among the three, and it generally lacks the prominent hump seen in the Smallmouth Buffalo. As its name suggests, the Black Buffalo tends to have the darkest coloration, ranging from dark olive to blackish or a gunmetal blue.