Red-eye Tetra Identification Guide
Identify the red-eye tetra by its bright red upper iris and the bold black bar across its tail base.
Read the full Red-eye Tetra encyclopedia entry →
Key identification features
- Deep-bodied, laterally compressed, silvery tetra reaching about 2.75 inches (7 cm)
- Vivid red coloring confined to the upper third of the eye's iris
- Broad black vertical bar on the caudal peduncle, just before the tail fin
- Scales along the upper back often show a faint golden sheen
- Fins are largely clear to pale yellow, without strong red or black edging
- Robust, moderately large body compared to most schooling tetra species
Common look-alikes
- Diamond tetra: similarly deep-bodied with a reddish eye tint but lacks the bold black bar at the tail base and shows sparkling scale flecks instead.
- Head-and-tail-light tetra: has a reflective gold spot near the tail rather than a solid black bar, plus a more slender body.
- Silver dollar (juvenile): rounder, flatter disc shape and much larger at maturity, without the red-eye tetra's dark caudal bar.
Where you'll see one
Widespread across slow rivers, streams, and flooded forest habitats of the central and lower Amazon and Paraguay-Paraná basins in South America.
Frequently asked questions
What is the clearest mark for identifying a red-eye tetra?
A bold black vertical bar on the tail base combined with red coloring limited to the top of the eye.
How do I tell it apart from a diamond tetra?
Look at the tail base: red-eye tetras have a solid black bar there, while diamond tetras lack any bar and show iridescent scale flecks instead.