Cardinal Tetra
(Paracheirodon axelrodi)
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Animal Type
Fish
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Exhibits
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Range
South America
Overview
Despite their small size, cardinal tetras are hard to miss. For one thing, they tend to hang out in large, slow-moving schools. Also, in the right light, they appear to glow, as if they're lit from within. Two bright, horizontal stripes run the entire length of their body, a thin band of turquoise atop a thicker band of red. Above and below these streaks of color, their delicate-looking fins are translucent.
Quick Facts
Learn more about cardinal tetras! Did you know cardinal tetras have something in common with humans? Both people and cardinal tetras are most active during the day.
Cardinal tetras are native to inland freshwater rivers, streams, creeks and wetlands of the Rio Negro and Orinoco basins of Brazil, Colombia, Venezuela and Boliva. They prefer shallow, slow-flowing tributaries with tea-colored water and dense forest cover. During seasonal flooding, when tributaries in the Amazon overflow their banks and submerge the surrounding forests, cardinal tetras migrate to swamps at tributaries' headwaters.
Cardinal tetras mostly feed on aquatic insects and larvae they find attached to submerged leaf litter, roots and plants. During the Amazon's wet season, they also eat algae that grows on submerged surfaces.
Fully grown adult cardinal tetras vary a bit in size and shape. Females are slightly larger than males; they grow up to 2 inches long and have deep, rounded bodies. Males can reach up to 1.5 inches in length and have long, slim, shallow bodies.
According to the IUCN Red List of Threatened Species, cardinal tetra populations are stable. They are considered a species of least concern.
Cardinal tetras are preyed upon by larger fish.
Explore Exhibit Residents
Learn more about the animals that share an exhibit with this one.
Freshwater Angelfish (Pterophyllum scalare)
Freshwater angelfish are one of the most recognizable tropical fish.
Giant South American River Turtle (Podocnemis expansa)
The giant South American river turtle is one of the largest freshwater turtles in the world.
White-Blotched River Stingray (Potamotrygon leopoldi)
This stingray has a distinctive pattern of dots, helping it blend into its riverbed habitat.
Bleeding Heart Tetra (Hyphessobrycon erythrostigma)
This tropical freshwater fish is adapted to living in slightly acidic water.
Giant Waxy Tree Frog (Phyllomedusa bicolor)
These frogs prevent themselves from drying out by wiping wax over their bodies.