The Brook Trout (Salvelinus fontinalis) are also called Eastern brook trout, mud trout, squaretail, and brook charr. It is a freshwater salmon fish to the family Salmonidae and native to Eastern North America but recently introduced in some parts of Europe and Asia. Brook trout are migratory fish with some reproducing in freshwater and spending their adult life in ocean water.

Brook Trout love areas with a spring-fed stream with sand and gravel. The animal can mate with relatively similar species to produce a hybrid. They are identified by their dark green to brown color, body with lighter shades but highly recognizable marble pattern.