The Longnose Sucker (Catostomus catostomus) is a freshwater fish commonly found in cold, clear streams and lakes across North America. They typically reach about 18-24 inches in length ... The Longnose Sucker (Catostomus catostomus) is a freshwater fish commonly found in cold, clear streams and lakes across North America. They typically reach about 18-24 inches in length and have a cylindrical body with a long, pointed snout. These bottom-feeders primarily consume invertebrates, algae, and detritus. Longnose Suckers are important for nutrient cycling in their ecosystems and are often used as bait fish by anglers.Click here to read more about Longnose Sucker.