Costello tetra  The Costello tetra is a species of characin from the Amazon basin and is found in Brazil and Peru. The specific name comes from Lake Hyanuary in Brazil. Other common names used in English are January tetra and green neon. The name "green neon" is also used for "Paracheirodon simulans". Costello tetras are found in the Amazon Basin. Costello tetras have been kept in the aquarium hobby. Some foods aquarists feed them include flakes, pellets, and live foods.