Photo: P. Petersen (CC BY 3.0) — via Wikimedia Commons
Xingu Black Neon Tetra (Moenkhausia heikoi)
A rare, striking shoaler from Brazil's Xingu rapids — bold eye markings and active schooling behaviour in one compact package.
Will it live with a Xingu Black Neon Tetra?
We compare each fish against your xingu black neon tetra on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Adolf's Cory✅ CompatiblePeaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Adolf's Cory in a shoal of 6+ or it gets stressed and nippy.
- Axelrod's Cory✅ CompatiblePeaceful · 5 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Axelrod's Cory in a shoal of 6+ or it gets stressed and nippy.
- Bandit Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 24–27 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Bandit Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Bloodfin Tetra✅ CompatiblePeaceful · 5.5 cm · Easy care · 18–28 °C (64–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blue Turbo Snail✅ CompatiblePeaceful · 5 cm · Medium care · 25–30 °C (77–86 °F)
- Both are peaceful, and their water overlaps around 25–28 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Checkered Barb✅ CompatiblePeaceful · 5 cm · Easy care · 20–25 °C (68–77 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Checkered Barb in a shoal of 6+ or it gets stressed and nippy.
- Cherry Barb✅ CompatiblePeaceful · 5 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 24–27 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Cherry Barb in a shoal of 6+ or it gets stressed and nippy.
- Cochu's Blue Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Cochu's Blue Tetra in a shoal of 8+ or it gets stressed and nippy.
- Firehead Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Firehead Tetra in a shoal of 8+ or it gets stressed and nippy.
- Five-banded Barb✅ CompatiblePeaceful · 5 cm · Easy care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 24–27 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Five-banded Barb in a shoal of 6+ or it gets stressed and nippy.
- Forktail Blue-eye✅ CompatiblePeaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Forktail Blue-eye in a shoal of 6+ or it gets stressed and nippy.
- Half-striped Penguin Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Half-striped Penguin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Harlequin Rasbora✅ CompatiblePeaceful · 5 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Honey Gourami✅ CompatiblePeaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Horseman Cory✅ CompatiblePeaceful · 5 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Horseman Cory in a shoal of 6+ or it gets stressed and nippy.
- Japanese Trapdoor Snail✅ CompatiblePeaceful · 5 cm · Easy care · 10–28 °C (50–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Julii Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 23–26 °C (73–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Masked Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Masked Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Mystery Snail✅ CompatiblePeaceful · 5 cm · Easy care · 20–28 °C (68–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Panda Corydoras✅ CompatiblePeaceful · 5 cm · Medium care · 20–26 °C (68–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Panda Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Rummy-nose Tetra✅ CompatiblePeaceful · 5 cm · Medium care · 23–29 °C (73–84 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Rummy-nose Tetra in a shoal of 6+ or it gets stressed and nippy.
- Skunk Corydoras✅ CompatiblePeaceful · 5 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Skunk Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Stoliczka's Barb✅ CompatiblePeaceful · 5 cm · Easy care · 20–26 °C (68–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Stoliczka's Barb in a shoal of 6+ or it gets stressed and nippy.
- Zebra Danio✅ CompatiblePeaceful · 5 cm · Easy care · 18–25 °C (64–77 °F)
- Both are peaceful, and their water overlaps around 24–25 °C — no size, zone or temperament conflicts.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
- Amano Shrimp⚠️ With cautionPeaceful · 5 cm · Easy care · 18–28 °C (64–82 °F)
- Xingu Black Neon Tetra may eat Amano Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Black Ruby Barb is semi-aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Black Skirt Tetra to harass Xingu Black Neon Tetra at times; give dense cover and watch them at feeding.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Chocolate Gourami⚠️ With cautionPeaceful · 5 cm · Hard care · 25–30 °C (77–86 °F)
- Different pH ranges (6.5–7.5 vs 4–6); doable if you sit in the shared band, but not ideal long-term.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Chocolate Gourami in a shoal of 6+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Expect Desert Goby to harass Xingu Black Neon Tetra at times; give dense cover and watch them at feeding.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Eastern Betta is semi-aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- GloFish Tetra is semi-aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Humpbacked Tetra and Xingu Black Neon Tetra are close in size, but the semi-aggressive one tends to dominate — add xingu black neon tetra in a group to spread the pressure.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Humpbacked Tetra in a shoal of 8+ or it gets stressed and nippy.
- Morse Code Corydoras⚠️ With cautionPeaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Odessa Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Odessa Barb to harass Xingu Black Neon Tetra at times; give dense cover and watch them at feeding.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
- Peaceful Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Peaceful Betta is semi-aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Silvertip Tetra⚠️ With cautionSemi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Silvertip Tetra and Xingu Black Neon Tetra are close in size, but the semi-aggressive one tends to dominate — add xingu black neon tetra in a group to spread the pressure.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Betta⚠️ With cautionSemi-aggressive · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Spotfin Betta is semi-aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Striped Red-Eye Puffer⚠️ With cautionAggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Expect Striped Red-Eye Puffer to harass Xingu Black Neon Tetra at times; give dense cover and watch them at feeding.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Wine Red Betta⚠️ With cautionAggressive · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Wine Red Betta is aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Size gap is too large (250 vs 5 cm): Alligator Gar will treat Xingu Black Neon Tetra as food.
- Alligator Gar is aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Size gap is too large (90 vs 5 cm): Clown Knifefish will treat Xingu Black Neon Tetra as food.
- Clown Knifefish clearly outsizes Xingu Black Neon Tetra and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Xingu Black Neon Tetra is bite-sized to a 100 cm predatory fire eel — it will be eaten.
- Fire Eel clearly outsizes Xingu Black Neon Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Koi (90 cm) is big enough to swallow the 5 cm Xingu Black Neon Tetra whole.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Size gap is too large (120 vs 5 cm): Redtail Catfish will treat Xingu Black Neon Tetra as food.
- Redtail Catfish is aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Xingu Black Neon Tetra is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Expect Spotted Gar to harass Xingu Black Neon Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Xingu Black Neon Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Wels Catfish is aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Xingu Black Neon Tetra is bite-sized to a 72 cm predatory wolf cichlid — it will be eaten.
- Wolf Cichlid is aggressive and may chase or nip the smaller Xingu Black Neon Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Xingu Black Neon Tetra care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 5 cm (2 in)
- Min tank size
- 70 L (18.5 gal)
- Temperature
- 24–28 °C (75–82 °F)
- pH
- 6.5–7.5
- Hardness
- 2–12 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Characidae
- Origin
- Brazil — Rio Xingu basin (Rio Iriri and associated rapids)
What is the Xingu Black Neon Tetra?
The Xingu Black Neon Tetra (Moenkhausia heikoi) is a compact characid from the Xingu river system in the Brazilian Amazon, formally described in 2004. It reaches about 5 cm (2 in) in length and carries a highly distinctive lateral pattern: a bold dark stripe running from the gill plate toward the caudal peduncle, paired with an iridescent counterpart and a large, reflective eye spot that catches light in a way the common Black Neon Tetra (Hyphessobrycon herbertaxelrodi) does not replicate. The two are unrelated despite the shared vernacular name.
In the aquarium, M. heikoi is peaceful and spends most of its time mid-water, schooling actively when kept in the groups the species requires. Its relative scarcity in the hobby — it turns up occasionally through specialist importers — makes it a rewarding target for the experienced keeper who values something out of the ordinary, provided the tank can replicate the clean, well-oxygenated, moderately fast-moving water of its native rapids.
Where does the Xingu Black Neon Tetra come from?
Moenkhausia heikoi is endemic to the Rio Xingu basin in Pará state, Brazil, with records concentrated in the Rio Iriri and the rocky, swift-flowing stretches that characterise this drainage. The Xingu is one of the Amazon’s clearest major tributaries: the substrate is granite boulders and coarse gravel, the water is warm but oxygen-rich because of constant agitation over rapids, and visibility can be high compared to blackwater systems further west.
The fish occupies turbulent mid-water zones in the wild, schooling in open water between boulders. This origin matters practically: it explains the species’ sensitivity to stagnant or poorly oxygenated conditions and its preference for visible current. The Xingu basin is also politically significant — the Belo Monte dam project has altered parts of it — so responsible hobbyists should confirm their fish come from sustainable sources.
What size tank does a Xingu Black Neon Tetra need?
The recommended minimum is 70 litres (about 18 US gal), and that number assumes a lean stocking of eight fish — the minimum group size the species needs to behave naturally. A 90–120 litre (24–32 gal) tank with a long horizontal footprint is a more comfortable fit for a shoal of ten or more, and it gives significantly more buffer for the water quality this species demands.
Choose a tank that prioritises length over height. The Xingu Black Neon Tetra is a mid-water shoaler that roams across the full length of the aquarium; tall, narrow tanks underserve it. A lid is sensible, as characteristically active tetras can jump when startled. Leave open swimming lanes between plants and hardscape so the school can move together freely.
What water parameters does the Xingu Black Neon Tetra need?
These fish come from some of the cleanest water in the Amazon basin. Replicate it as closely as possible:
- Temperature: 24–28 °C (75–82 °F). Stable warmth is more important than chasing a specific number within that range.
- pH: 6.5–7.5. A mildly acidic to neutral reading suits the species; avoid hard alkaline conditions.
- Hardness: 2–12 dGH. Soft to moderately soft water is preferred; very hard tap water should be diluted with RO or rain water.
- Flow and oxygenation: Strong surface agitation and visible current are not optional. A powerhead, wavemaker or spray-bar return aimed along the tank surface closely mimics the rapids habitat and keeps dissolved oxygen high.
- Filtration: Robust mechanical and biological filtration with a high turnover rate. Weekly water changes of 25–30 % are a baseline; these fish are intolerant of accumulated nitrates.
Newly imported specimens can be delicate while acclimating, so drip-acclimate slowly and test water carefully before and after.
What do Xingu Black Neon Tetras eat?
M. heikoi is an omnivore in the wild, picking invertebrates, plant material, and organic particles out of the water column and from between rocks. In the aquarium, a varied diet produces the best colouration and condition:
- Staple: A quality small-granule or fine flake food fed in amounts the fish consume within 2–3 minutes, once or twice daily.
- Protein supplements: Frozen or live daphnia, brine shrimp nauplii, micro-worms and cyclops. These small invertebrates closely match natural prey size and trigger active feeding behaviour.
- Vegetable matter: A small amount of blanched spinach, spirulina-based foods or algae wafer crumbs rounds out the diet.
Feed at intervals timed around the current in the tank — these fish are used to picking food out of moving water and will readily intercept sinking items mid-column.
How do Xingu Black Neon Tetras behave — and who can live with them?
The Xingu Black Neon Tetra is peaceful and poses no threat to any tank-mate of similar or larger size. Its own wellbeing, however, depends heavily on group size: a single fish or a pair of three will skulk, lose colour, and show stress markings. Eight is the minimum; ten or more in a spacious tank produces the cohesive, swirling schooling behaviour the species is kept for.
Ideal companions share the same soft, warm, moderately moving water requirements and occupy different zones of the tank:
- Bottom level: Corydoras species that tolerate gentle current, dwarf Otocinclus, smaller Hypancistrus plecos.
- Mid-level companions: Pencilfish (Nannostomus spp.), similarly sized peaceful tetras, Microdevario rasboras.
- Upper level / specialist: Apistogramma dwarf cichlids (kept at matching pH) as a centrepiece, provided the tank is large enough to give the school open space.
Avoid fin-nippers (many Barbus and Puntius species), large boisterous cichlids, and any species requiring hard alkaline water. For a full compatibility list, see Xingu Black Neon Tetra tank mates.
How do you tell male and female Xingu Black Neon Tetras apart?
Sexual dimorphism in M. heikoi is subtle, as is typical of small schooling tetras. Females are slightly fuller and rounder in the belly, particularly when approaching spawning condition, and may appear marginally deeper-bodied when viewed from above. Outside of a conditioning period, the sexes are difficult to distinguish reliably by eye. Colour pattern and stripe intensity are broadly similar in both. Experienced breeders sometimes select females by gently viewing fish from above in a shallow container, choosing the individuals with the widest abdominal profile.
Can you breed Xingu Black Neon Tetras in captivity?
Breeding is rated hard and is a project for experienced characin breeders. The basic method follows the scatter-spawning pattern common to the family:
- Condition a target group of well-fed adults on live and frozen foods for several weeks.
- Set up a breeding tank of around 30–40 litres with very soft, acidic water (pH 6.0–6.5, 1–4 dGH), dim lighting, and a fine spawning mop or clump of Java moss to catch eggs. A bare bottom makes egg collection easier.
- Introduce a small group (a trio of one male to two females, or a small shoal) in the evening. Spawning, if it occurs, typically happens in the morning over fine-leaved plants or mops.
- Remove adults promptly after spawning — M. heikoi is an egg-scatterer with no parental instinct and will consume eggs.
- Raise fry on infusoria or commercial fry foods initially, progressing to freshly hatched brine shrimp nauplii once the fry are large enough. The fry are small and vulnerable to low water quality.
Consistent breeding success in captivity is rarely reported in the hobby literature, largely because the species is uncommon in collections. Patience, excellent water quality, and live foods throughout conditioning are the key variables.
What diseases affect Xingu Black Neon Tetras?
Like most small tetras, M. heikoi is susceptible to the diseases that follow from compromised water quality or the stress of poor group dynamics:
- Ich (white spot disease): Small white granules on fins and body. Triggered by temperature drops or stress. Prevented by stable heat and clean water.
- Velvet (Oodinium): A fine gold or rust-coloured dusting, most visible under a torch light raked across the body. Highly contagious; quarantine any new additions for at least 2–4 weeks.
- Neon tetra disease (Pleistophora hyphessobryconis): A microsporidian infection causing pale, irregular blotching along the lateral line. There is no effective treatment; infected fish should be humanely euthanised and removed to prevent spread. Purchasing from reputable sources reduces risk.
- Fin rot and bacterial infections: Almost always secondary to poor water quality or physical damage from fin-nippers. The primary fix is the water, not the medication.
- Internal parasites: Occasionally seen in wild-caught imports. A quarantine protocol with observation is the best screen before introducing new stock to an established tank.
Health note: disease identification and medication dosing are beyond the scope of a care profile. For sick fish, confirm symptoms carefully against a reputable veterinary or fish-health resource before treating, and always address water quality first.
How long do Xingu Black Neon Tetras live?
A well-maintained M. heikoi lives 3–5 years in captivity. That lifespan is reasonable for a small characid, but it is contingent on consistently good care: stable water parameters within the species’ range, a shoal of at least eight, a varied diet, and a stress-free environment free of aggressive tank-mates. Fish that are kept in small groups or in hard, poorly oxygenated water rarely thrive into the upper end of that range. Because this species is wild-caught more often than captive-bred, newly acquired specimens may have experienced handling stress; a careful, patient acclimation period pays dividends in longevity.
Frequently asked questions
How many Xingu Black Neon Tetras should I keep together?
Keep at least eight, and more if tank space allows. In the wild these fish live in large shoals in swift water. Small groups show stress, reduced colouration and skittish behaviour. Ten or more in a spacious tank brings out their best schooling display.
Is the Xingu Black Neon Tetra the same as the Black Neon Tetra?
No. The common Black Neon Tetra is Hyphessobrycon herbertaxelrodi, a completely different species that is widely available and easy to find. Moenkhausia heikoi is a rarer Xingu endemic collected occasionally for the specialist trade and commands a higher price.
What you need to keep a xingu black neon tetra
The baseline is a heated, filtered 70 L+ tank: a reliable heater to hold 24–28 °C (75–82 °F), a gentle filter that won't batter a xingu black neon tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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