Common name
Red-eye tetra
Scientific name
Bario sanctaefilomenae
Category
Freshwater fish
Group
Tetras and characins
Environment
Freshwater
Origin
Paraguay, Paraná, Uruguay and São Francisco river systems of South America
Care level
Beginner to intermediate
Adult size
Up to about 7 cm standard length
Expected lifespan
About 4–6 years
Minimum housing
At least 120 L for a group of ten or more, with a long open swimming area
Temperature
22–27 °C
pH
6.0–8.0
Hardness / minerals
Soft to moderately hard
Salinity
Freshwater
Lighting
Moderate with shaded refuge
Placement / swimming zone
Middle water

Identity and search names

Single-species profile for Bario sanctaefilomenae. Moenkhausia sanctaefilomenae is a homotypic synonym under the 2024 phylogenomic classification. Search names include Red-eye tetra, Bario sanctaefilomenae, Moenkhausia sanctaefilomenae, Tetragonopterus sanctaefilomenae.

Environment and housing

Long aquarium with robust planted margins, open swimming space, stable filtration and good oxygenation

Feeding and nutrition

Feeding ecology: Omnivorous; use varied prepared foods with small live or frozen invertebrates and some plant material

Feeding routine: Offer modest varied meals once or twice daily and prevent dominant fish monopolising food

Breeding and reproduction

Egg-scattering characin; adults provide no care and may eat eggs.

Breeding plan: Egg-scattering characin; adults provide no care and may eat eggs. Parental care: No parental care; adults may consume eggs.

Compatibility plan

Choose active similarly sized fish; avoid tiny timid species and slow long-finned tankmates

Filtration and aeration

Filtration: Use mature biological filtration sized for the adult group and feeding load, with protected intakes and a flow pattern suited to the species.

Aeration: Maintain dependable gas exchange and dissolved oxygen with surface agitation or supplementary aeration while preserving sheltered resting areas.

Maintenance

Test water routinely, remove waste and uneaten food, service filtration without destroying biofilm and review stocking as animals mature.

Adult projected load

Adult projected load includes mature body mass, social-group size, territorial space, oxygen demand, feeding waste and breeding output.

Welfare and risk

Maintain the stated adult space and social structure, verify feeding and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. A small group in a short tank encourages chasing and fin damage. This is not a quiet nano tetra.

Main risk: A small group in a short tank encourages chasing and fin damage. This is not a quiet nano tetra.

Biosecurity and release

Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.

Overridable warnings

Warnings may be overridden only after adult size, group structure, filtration, aeration, compatibility and maintenance capacity are recorded.

Sources