Black phantom tetras are social fish known for dark flank markings and the males’ extended fins. Keep them in a group with swimming space and planted retreats. Displays between males can be normal, but persistent chasing, a fish unable to feed, or injuries need attention.
Leave room for the whole group
Plan for at least six, preferably a larger group where the aquarium can support it. For a community setup, choose a tank with a useful length and width rather than judging capacity from liters or gallons alone.
A roughly 80 cm-long aquarium provides a more suitable starting footprint than a small cube. Seriously Fish’s profile lists an 80 × 30 cm base and describes the social requirements. The species is also widely sold under the older name Hyphessobrycon megalopterus.
Break up sight lines without blocking swimming
Arrange plants and suitable hardscape around open water. Fish should be able to leave a display or chase and reach cover. Do not solve aggression by packing so many decorations into the tank that no swimming room remains.
Moderate, partly shaded lighting can suit this layout. Water wisteria or a planted background can provide cover, provided growth is kept trimmed.
Keep water conditions stable
Use an established filter and compatible freshwater conditions. The species profile lists 20–28°C (68–82°F), pH 5.0–7.0, and soft to moderately hard water. These are reference ranges, not instructions to move an occupied tank rapidly toward an endpoint.
Confirm ammonia and nitrite are undetectable and keep a consistent maintenance routine. Driftwood can influence water chemistry, but it is not a guaranteed pH setting. Use the testing checklist before changing the water preparation.
Assess tank mates by behavior
Other peaceful fish of a compatible size and water preference may work. Do not assume black phantoms can never nip fins, or that every betta, guppy, or gourami will be a suitable companion.
Watch the actual community for persistent pursuit, hiding, fin damage, or missed meals. Review group size, layout, space, and companions when those appear. Torn fins should not simply be dismissed as a normal cost of male displays.
Feed a varied, appropriately sized diet
Use a suitable complete food as a staple, supplemented by appropriately sized frozen or live foods. Distribute small portions so shy fish can feed without leaving waste behind. Adjust the amount to the animals rather than applying one timing rule to every aquarium.
Distinguish courtship from successful breeding
Males often develop more pronounced fins and display to each other; females may show redder fins and a fuller body. Appearance alone is not proof of health, sex, or spawning.
These tetras scatter eggs and do not provide parental care. A controlled attempt needs a separate plan for protecting eggs and feeding tiny fry. Avoid adding a rigid fry-feeding timetable to a community tank where the hatch date and food size are unknown.
For a smaller species to compare, see ember tetras. Keep the group healthy through the regular maintenance routine.
