Description
The red-eye tetra is the large, sociable characin of the active community tank: about 7 cm, a silver body with a black band on the peduncle and a bright red ring above the pupil that gives the fish its name.
It is hardy, needs no special water and is bred in the millions. Its drawback is temperament: it is boisterous and competes for everything, so it intimidates slow or shy fish such as anabantoids or dwarf cichlids.
Behavior
Peaceful but restless; in a group of six to eight it spends its energy among its own and leaves the neighbours alone.
It lives well with other tetras of similar size, barbs, rainbowfish and danios.
Avoid housing it with bettas, calm gouramis and dwarf cichlids, which end up displaced, and with much smaller fish.
Habitat
Moenkhausia sanctaefilomenae lives in Brazil, Paraguay and Argentina, mainly in clearwater rivers that feed the Pantanal. Unlike the murky Amazon, a lot of aquatic vegetation grows there, with rafts of floating plants and beds of Echinodorus.
That is why it prefers a planted tank that is not too bright, and appreciates it more than a bare set-up.
Tetra ojo rojo is a schooling species, which means that in the wild it lives and moves in large, coordinated groups.
Keep at least 6 individuals so they feel comfortable and their stress level stays low.
Details
🌊 Water parameters
🐠 Minimum tank size
Breeding
An egg scatterer with no parental care: the eggs fall among fine plants and the adults devour them. It is bred in a separate tank with soft water and low light, removing the adults afterwards.
Diet
An undemanding omnivore.
- Staple: quality flake or small pellets.
- Supplement: frozen food and some vegetable matter, such as spirulina.
It eats greedily and sometimes nibbles tender plants.
What about your tank?
Enter your tank's values to see only the compatible species that fit them. Litres apply to fish.
Compatible fish
General guidance based on water parameters, behaviour and known exceptions; always review the individual animals' and aquarium's specific needs.
They share water: pH 6–7 and 24–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–8 and 23–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–7 and 23–26 °C.
They share water: pH 6–7 and 23–26 °C.
They share water: pH 7–8 and 26 °C. They only meet at the very edge, so the tank has to hold that value.
They share water: pH 6–7.8 and 22–25 °C.
They share water: pH 6–7 and 22–26 °C.
They share water: pH 6–7 and 24–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–7 and 24–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–8 and 24–26 °C.
They share water: pH 6–7.5 and 25–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6.5–8 and 24–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–7.5 and 22–25 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6.5–7.5 and 22–24 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6.5–8 and 22–26 °C.
They share water: pH 7.5–8 and 26 °C. They only meet at the very edge, so the tank has to hold that value.
They share water: pH 6–7.5 and 25–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–7 and 24–26 °C.
They share water: pH 6–7.5 and 26 °C. They only meet at the very edge, so the tank has to hold that value.
They share water: pH 6–7 and 23–26 °C.
They share water: pH 6–7.5 and 23–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6–7 and 24–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 7.5–8 and 24–26 °C.
They share water: pH 7.5–8 and 24–26 °C.
They share water: pH 6–7 and 22–26 °C.
They share water: pH 6–6.5 and 23–26 °C.
They share water: pH 6.5–7.2 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 24–26 °C.
They share water: pH 6–8 and 25–26 °C.
They share water: pH 6–8 and 22 °C. They only meet at the very edge, so the tank has to hold that value.
They share water: pH 6.5–8 and 22–24 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7 and 23–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6–7.2 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6–7.2 and 22–26 °C.
They share water: pH 6–7.2 and 24–26 °C.
They share water: pH 6–7.2 and 24–26 °C.
They share water: pH 6–7 and 26 °C. They only meet at the very edge, so the tank has to hold that value.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6–8 and 25–26 °C.
They share water: pH 6–6.5 and 24–26 °C.
They share water: pH 6–7 and 24–26 °C.
They share water: pH 6–7 and 23–26 °C.
They share water: pH 6–8 and 23–26 °C.
They share water: pH 6–7.2 and 22–26 °C.
They share water: pH 6–7.5 and 23–26 °C.
They share water: pH 6–8 and 24–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 6–7.5 and 23–26 °C.
They share water: pH 6–8 and 22–26 °C.
They share water: pH 6–8 and 24–26 °C.
They share water: pH 6–7.5 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
Compatible invertebrates
General guidance based on water parameters, behaviour and known exceptions; always review the individual animals' and aquarium's specific needs.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6–6.5 and 22–24 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 7–8 and 22–25 °C.
They share water: pH 7.5–8 and 24–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7.5–8 and 26 °C. They only meet at the very edge, so the tank has to hold that value.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6–6.8 and 22–24 °C.
They share water: pH 6–6.8 and 22–24 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6.5–7.5 and 23–26 °C.
They share water: pH 6.5–7.5 and 23–26 °C.
They share water: pH 7–8 and 23–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 6.5–7.5 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6.5–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 7–8 and 22–26 °C.
They share water: pH 6–6.5 and 22–24 °C.
Sources
- FishBaseFroese, R. and D. Pauly. Editors. 2026. FishBase. World Wide Web electronic publication.
- Seriously FishSeriously Fish. Bario sanctaefilomenae. Ficha de especie; consultada 2026-10.
Hardness: FishBase gives 5-19 dH and Seriously Fish, 3-20 dGH. The profile uses 3-20, the widest range. Seriously Fish already lists it as Bario sanctaefilomenae; the profile keeps Moenkhausia, the name accepted by GBIF.
Litres per fish and minimum tank height and depth: the profile's own judgement. Seriously Fish gives only the tank base and FishBase gives no tank sizes.
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