The cardinal tetra is a small freshwater fish native to the Amazon River basin in South America. It is known for its vibrant blue and red coloration, making it a popular choice for home aquariums. Typically, cardinal tetras grow to about 1.5 inches in length and thrive in schools of six or more, which helps reduce stress and encourages natural behavior. These fish prefer warm, soft, and slightly acidic water, often found in densely planted environments. They are peaceful and can coexist with other small fish species, such as neon tetras and guppies. Proper care and a suitable habitat are essential for their well-being.