Brook stickleback

The Brook stickleback is a small, freshwater fish characterized by its olive-green to brown color and distinctive spines before its dorsal fin. Originating from North America, particularly from northern United States to Canada, it is recognizable by its slender body and the presence of two to four sharp spines. Despite its interesting behavior and adaptability to different environments, it is not particularly well-known or commonly kept in the aquarium hobby. This is partially due to its aggressive nature and specific habitat requirements, making it more of a niche interest among fish enthusiasts.