The term 'Bigmouth Fish' is a common name for the species of fish known as the largemouth BASS. This species of fish is native to North America and is found in freshwater lakes, rivers, and streams. It is a popular game fish and is highly sought after by anglers due to its size and strength. The largemouth BASS can grow up to 20 inches in length and weigh up to 10 pounds. It is an aggressive predator and feeds on smaller fish, frogs, and crayfish.