Cardinal Tetra (Paracheirodon axelrodi) is a small freshwater characin native to the upper Orinoco and Rio Negro drainage areas of South America, especially blackwater streams, shaded forest tributaries, and seasonally flooded habitats with soft, acidic water and heavy cover.

This species is known for its vivid blue lateral stripe and deep red lower body that extends nearly the full length of the fish. Its small size, schooling behavior, and high-contrast coloration make it one of the most recognizable tetra species in the aquarium trade.

Cardinal Tetras are peaceful schooling fish that look best in groups, especially in planted aquariums with darker backgrounds, gentle flow, and stable water quality. Their color and movement add a bright, natural midwater presence to planted and peaceful community aquariums.