Mississippi designated the largemouth bass (Micropterus salmoides) in 1974.. This black bass (an elongated sunfish) lives in quiet, vegetation-rich waters.

Adult largemouth bass are active predators in the aquatic ecosystem, feeding on other fish and large invertebrates (such as crayfish). Large bass will also prey upon smaller bass. Largemouth bass can reach a length of more than twenty inches and weigh more than fifteen pounds. The largemouth bass is also a state symbol in Florida, Alabama, and Georgia.

Source:

Largemouth Bass: TX Parks and Recreation
State Freshwater Fish - Largemouth Bass: Florida OHCP

Links:

State Fish & Water Life Symbols - 50 States