Characiformes is an order of freshwater fish that includes species commonly known as characins, tetras, and piranhas. They are primarily found in tropical and subtropical regions of South America, Africa, and parts of Central America. Characiformes are characterized by their diverse body shapes, sizes, and colors, with many species exhibiting bright, vibrant hues. These fish typically have a distinctive adipose fin, which is a small, fleshy fin located between the dorsal fin and the tail. Characiformes are known for their schooling behavior, often found in groups, and they play important roles in their ecosystems as both predators and prey.