Definition
*Gasterosteus* is a genus of sticklebacks, small fish known for their spines. The most well-known species is the three-spined stickleback (*Gasterosteus aculeatus*). They inhabit freshwater and marine environments and exhibit complex social behaviors. Males build nests and display bright colors to attract mates. Think of them as the interior designers 🎨 and dancers 💃 of the fish world! They have remarkable adaptability.