Congo tetra

Identity and search names

Single-species profile for Phenacogrammus interruptus. Do not merge it with other Phenacogrammus or Alestidae sold under broad “Congo tetra” labels.

Environment and housing

Long open swimming lane, shaded planted or wood margins, moderate flow, clean oxygenated water and a secure lid

Feeding and nutrition

Feeding ecology: Omnivorous micropredator; insects, crustaceans and quality prepared foods

Feeding routine: Offer small varied meals once or twice daily and distribute food through the school

Breeding and reproduction

Egg scatterer; use a separate soft-water breeding setup because adults eat eggs

Parental care: No post-spawning parental care

System demands

Filtration: Use mature biological filtration sized for the adult stock and feeding load, with guarded intakes and a flow pattern the species can use without continual effort.

Aeration: Maintain strong gas exchange and stable dissolved oxygen, especially overnight, during warm weather, medication, crowding or any interruption to filtration.

Maintenance: Test ammonia and nitrite after changes or abnormal behaviour; remove waste from the occupied zone and perform regular water changes matched to temperature and mineral chemistry.

Detailed husbandry

Identity scope

Single-species profile for Phenacogrammus interruptus. Do not merge it with other Phenacogrammus or Alestidae sold under broad “Congo tetra” labels.

Adult size and space

Males up to about 8 cm; females commonly around 6 cm. At least 240 L with a 120 cm or longer swimming length for eight or more. Adult dimensions, activity, social structure and waste production matter more than sale size.

Social structure

Keep eight or more with both sexes represented and enough space for display

Swimming zone

Primary zone: Mid water. Keep that zone usable and provide unobstructed feeding access, movement and refuge appropriate to the species.

Feeding ecology

Omnivorous micropredator; insects, crustaceans and quality prepared foods

Feeding plan

Offer small varied meals once or twice daily and distribute food through the school

Water stability

Maintain 23–27 °C; pH: 6.0–7.5; hardness/minerals: Soft to moderately hard. Stable temperature, oxygen, mineral chemistry and nitrogen-cycle control matter more than chasing one exact number.

Habitat structure

Long open swimming lane, shaded planted or wood margins, moderate flow, clean oxygenated water and a secure lid

Compatibility plan

Choose peaceful similarly sized fish; avoid fin-nippers, large predators and tiny timid species

Breeding plan

Egg scatterer; use a separate soft-water breeding setup because adults eat eggs. Parental care: No post-spawning parental care. Do not trigger reproduction without capacity for aggression, eggs or fry and lawful long-term placement.

Quarantine

Quarantine new fish in a separate cycled aquarium with dedicated nets, containers and siphons. Match temperature and mineral chemistry gradually, confirm normal feeding, respiration, skin, fins and waste, and never pour transport water into the established aquarium.

Welfare checks

Track fin condition, school cohesion, feeding access, respiration, body fullness and whether males can display without chronic chasing.

Biosecurity and release

Never release fish, eggs, fry, aquarium water, sediment, plants or foods into drains, dams or natural waterways. Confirm the exact accepted identity against current Australian import requirements and applicable South Australian rules before import, sale or movement; import eligibility never authorises release or wild collection.

Main risk

Congo tetras are not small-bodied nano tetras. Adult males have long fins and need a large school, substantial swimming length and non-nipping tankmates.

Adult Projected Load

Moderate for the planned adult stock. Calculate filtration, oxygen and swimming space from the full adult size (Males up to about 8 cm; females commonly around 6 cm) and social group (Keep eight or more with both sexes represented and enough space for display), not the juvenile sale size.

Filtration

Use mature mechanical and biological filtration with protected intakes and enough turnover for the adult group while preserving species-appropriate current and refuge.

Aeration

Provide strong gas exchange and backup aeration; increase oxygen support before warm weather, heavy feeding, crowding, medication or filter interruption reduces the safety margin.

Maintenance

Remove uneaten food and bottom waste, clean prefilters before flow falls, test ammonia and nitrite after changes, and perform regular temperature- and chemistry-matched water changes.

Overridable Warnings

Congo tetras are not small-bodied nano tetras. Adult males have long fins and need a large school, substantial swimming length and non-nipping tankmates.

Welfare and risk

Track fin condition, school cohesion, feeding access, respiration, body fullness and whether males can display without chronic chasing. Congo tetras are not small-bodied nano tetras. Adult males have long fins and need a large school, substantial swimming length and non-nipping tankmates.

Sources

• Eschmeyer’s Catalog of Fishes — Phenacogrammus interruptus — Accepted-name, synonym and taxonomic-placement cross-check
• IUCN Red List search — Phenacogrammus interruptus — Conservation-status and wild-provenance cross-check
• Australian Government — importing live ornamental fish — Australian import pathway and biosecurity requirements
• PIRSA — South Australian noxious fish list — South Australian possession, trade and release context
• Eschmeyer’s Catalog of Fishes current search — Phenacogrammus interruptus — Current accepted-name, synonym, distribution and habitat cross-check