Care guide · Freshwater · fish

Loreto tetra

Hyphessobrycon loretoensis

Scientific live-colour illustration of Hyphessobrycon loretoensis by Jürgen Scholz; CC BY 4.0. Not an aquarium photograph. Photo: A. Zarske, D. Bork and H.J. Franke; illustration by Jürgen Scholz · Source · CC BY 4.0Converted from PNG to optimized JPEG; dimensions and content retained.

The Loreto tetra (Hyphessobrycon loretoensis) is a small, peaceful South American shoaling fish with a dark lateral band and orange-red tail. Keep it in a group in a mature, calm aquarium with both cover and open swimming space. Specialist aquarium sources give 22–28°C, pH 5.0–7.0 and GH 1–8; FishBase reports partly broader and partly different values. The source differences are explained below. It uses midwater, takes small animal and plant foods, and is vulnerable around larger or boisterous tankmates. A base of about 60 × 30 cm is a documented lower bound, not a guarantee for every community mix.

Plan your aquarium →

At a glance

Temperature: 22–26 °C
pH: 5.5–7.0
GH: 1–8 °dGH
Aquarium length: At least 60 cm
Minimum aquarium volume: At least 54 L
Adult size: Up to 2.4 cm
Group size: At least 8 individuals
Temperament: Peaceful

About this species

Hyphessobrycon loretoensis was described by Ladiges in 1938 and is treated as valid by Catalog of Fishes, FishBase and ITIS. It belongs to Characiformes. FishBase follows the recent family treatment Acestrorhamphidae, while ITIS still displays Characidae. Classification of American tetras has recently changed and sources may lag or use different systems, so family placement is less stable than the species identity.

This is a small, slender fish. Seriously Fish reports 25 mm standard length (SL); FishBase gives a maximum of 2.4 cm SL. These are similar but not identical source records and do not promise that every aquarium fish reaches exactly that size. A dark lateral stripe and orange to brick-red tail are useful features. Seriously Fish notes that mature females are rounder and slightly larger; body shape alone is not a certain sexing method.

Loreto tetra is used here as a clear English common name. Always use the scientific name for identification because trade names differ between markets.

Natural habitat

The species is native to the upper Amazon basin. Seriously Fish lists records in Colombia, Peru and Ecuador, including forest streams and smaller tributaries. FishBase lists the upper Amazon in Peru, while additional locality records occur in specialist literature. Its known range is therefore broader than a single river.

Forest streams are characterised by overhanging vegetation, roots, branches and leaf litter. Decomposing leaves can tint the water a weak tea colour. This describes habitat; it is not a requirement to darken aquarium water. A safe aquarium mainly reproduces structure: sheltered areas, shaded spots and open water.

A species recorded in a region is not automatically compatible with every plant or tankmate from that region. Keep the aquarium clean and stable, and avoid unsupported exact flow or mineral targets.

Aquarium and layout

Seriously Fish recommends a base of about 60 × 30 cm and approximately 54 litres as the smallest aquarium to consider. Treat this as a specialist lower-bound recommendation for the fish group, not a guarantee that every community combination will fit. A longer aquarium gives the shoal more usable swimming room than a taller tank of equal volume.

Sand, driftwood roots and branches reflect the described habitat; a planted setup can also work. Leave open swimming space and place cover mainly along the sides and back. Dried leaves can add structure, but use only aquarium-safe material and continue normal maintenance. A lid is sensible for small, easily startled fish.

Add fish only to a fully cycled aquarium. Provide gentle, even filtration and gas exchange. Check that every fish can feed. Quarantining new arrivals helps reduce the risk of introducing pathogens to an established tank.

Water conditions

Seriously Fish gives 22–28°C, pH 5.0–7.0 and GH 1–8 dGH. FishBase reports 22–26°C, pH 5.5–7.5 and a hardness maximum of 15 dH without a lower bound. As a practical shared range, we use 22–26°C and pH 5.5–7.0; for GH we use the fully bounded aquarium range 1–8 dGH from Seriously Fish. This is a cautious overlap of source values, not an experimentally established optimum.

Keep conditions stable and consider the fish’s source and acclimation history. Do not rapidly change pH or hardness to reach a number. FishBase field data and aquarium care recommendations are not interchangeable: a wild measurement is not automatically a husbandry target.

Test temperature, pH and hardness with suitable methods. Ammonia and nitrite should not be detectable in a stable, cycled aquarium; perform appropriate regular water maintenance. No dependable species-specific KH target was found, so none is given.

Behaviour and group size

Seriously Fish describes the Loreto tetra as very peaceful and a shoaling fish. It recommends a mixed group of at least eight to ten. This is practical aquarium guidance, not a controlled behavioural trial or universal biological minimum. A group can support more natural behaviour and social security.

The species uses the water column. Small, calm characids may be candidates if water conditions overlap and the aquarium offers enough swimming space. Similar temperature or pH alone does not prove compatibility: also assess adult size, predation, territory, swimming zone, group needs and food competition. The linked neon tetra is therefore suitable only under conditions: maintain a proper group of each species, provide more room than the minimum setup and check that the smaller Loreto tetras get food. This is a cautious assessment from species profiles, not a trial report.

Avoid large fish able to swallow small tetras, active hunters and fish that dominate the middle water. Persistent hiding, damage or fish not eating means the stocking should be reconsidered.

Feeding

The natural diet is probably omnivorous and includes small invertebrates and crustaceans, filamentous algae and fallen fruit. In aquaria the fish accepts dried foods, but Seriously Fish recommends variety, including fine dry food and small live or frozen foods such as mosquito larvae and small water fleas.

Choose particle size for this small fish; sources do not specify an exact commercial food size. Offer small portions and check that shy individuals actually eat. Larger tankmates may outcompete them, so spread food across more than one spot if needed. Remove leftovers to avoid unnecessary water pollution.

No reliable source establishes one exact daily schedule or portion. Vary suitable foods and adjust amounts to condition and intake.

Breeding

Seriously Fish describes this species as a free-spawning egg scatterer with no parental care. A mature aquarium may occasionally produce fry, but that does not guarantee successful breeding. Adults may eat eggs or fry.

For a planned attempt, the source describes a separate mature aquarium with subdued light and a protected base (such as fine-leaved moss, a spawning mop or suitable mesh) to reduce adult access to eggs. It suggests slightly acidic to neutral water and a temperature toward the upper end of the care range. Treat this as a starting point from one specialist profile; do not change water conditions abruptly.

First foods must be extremely fine; the source mentions infusoria or suitable micro-food, followed by Artemia nauplii or microworms once fry can take them. Exact development times are not set here. Keep adults and fry safe and monitor water quality.

Sources & review

This care guide draws on several specialist sources and was last checked on 16 October 2026.

View the sources