Xingu Black Neon Tetra 'Rio Xingu' (Moenkhausia heikoi)

Common Name

Xingu Black Neon Tetra

Scientific name

Moenkhausia heikoi   |   Origin, Rio Xingu, Pará, Brazil

Origin and Habitat

Native to the Rio Xingu in Pará, Brazil. In the middle Xingu they cruise fast moving, highly oxygenated channels with rocky bottoms, using boulder fields and shaded seams to rest between bursts of current. Water is clear, warm, and low in hardness with seasonal variation in flow and water level. You will often see them schooling over rock and sand where drifting micro foods collect.

Temperature and Water Conditions

Preferred range is 75 to 82 F, which is 24 to 28 C. Wild water is typically soft and mildly acidic to near neutral, commonly about pH 6.0 to 7.2. We do not recommend chasing exact numbers for routine care. Stable, clean, well oxygenated water is far more important. A bit of current and strong surface agitation will make them feel at home.

Appearance and Size

Slender and luminous with a bold black lateral bar and bright reflective edging that gives a black neon impression in motion. Adults are usually about 5 to 7 cm total length, roughly 2 to 2.8 inches, with some reports of larger individuals. Males may show slightly deeper body sheen and finer fin edges.

Diet in the Wild

Micropredator and picker. In the Xingu they take tiny insect larvae, micro crustaceans, and edible biofilm drifting in current lanes and around rock breaks.

Feeding in Captivity

Offer quality micro pellets and fine flakes, plus small live or frozen foods such as baby brine shrimp, daphnia, cyclops, and finely chopped bloodworm. Several small feedings bring out color and schooling behavior. A bit of flow helps keep food suspended so the group can feed midwater.

Behavior and Tank Setup

Peaceful and best in a real school. Keep at least eight so they display natural formation runs and confident midwater gliding. Use a long footprint tank with strong aeration, gentle to moderate current, rock piles or wood for breaks, and open lanes for swimming. Ideal companions include other calm characins, robust corys that enjoy current, and Xingu friendly plecos that appreciate oxygen rich water.

Breeding

Presumed open water or plant spawning egg scatterer like many Moenkhausia, documented hobby spawnings are scarce. For a breeding attempt, condition a small group on abundant live and frozen foods, then set a separate tank with very soft water, fine leaved plants or spawning mops, marbles or mesh to catch eggs, dim light, and a gentle trickle of flow. Introduce a well conditioned pair or trio late in the day, many tetras spawn at first light. Remove adults after spawning. Eggs typically hatch within one to two days depending on temperature. Start fry on infusoria or paramecium, then transition to newly hatched brine shrimp and finely powdered fry foods while you maintain pristine water with tiny daily changes.

Quick Facts

• Scientific name: Moenkhausia heikoi
• Origin: Rio Xingu, Pará, Brazil
• Adult size: usually about 5 to 7 cm, roughly 2 to 2.8 inches
• Temperature: 75 to 82 F (24 to 28 C)
• Wild pH: about 6.0 to 7.2, soft to near neutral water
• Temperament: peaceful schooling tetra
• Diet: micro predator and picker, accepts quality prepared and small frozen foods
• Breeding: likely egg scatterer, plant or open water, remove adults after spawning

Tropical Fish Co. Notes

A school of Xingu Black Neons looks electric over rock and sand, the dark bar and bright edging flash with every turn. They remain uncommon in the hobby and arrivals tend to be limited and seasonal, so a healthy group becomes a showpiece and a great candidate for a home bred line. If you already keep Xingu plecos, these tetras are a perfect midwater partner that completes the river feel.