Photo: harum.koh from Kobe city, Japan (CC BY-SA 2.0) — via Wikimedia Commons
Red Phantom Tetra (Hyphessobrycon sweglesi)
A jewel-red schooling tetra from the Orinoco blackwaters, with a bold shoulder spot and graceful trailing fins that glow under low light.
Will it live with a Red Phantom Tetra?
We compare each fish against your red phantom tetra on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- African Dwarf Frog✅ CompatiblePeaceful · 4 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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Amapá Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 24–27 °C (75–81 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
- Black Phantom Tetra✅ CompatiblePeaceful · 4.5 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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Phantom Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blue Danio✅ CompatiblePeaceful · 4 cm · Easy care · 21–26 °C (70–79 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Blue Danio in a shoal of 6+ or it gets stressed and nippy.
- Blue Emperor Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Blue Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cardinal Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
- Emperor Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Flame Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Flame Tetra in a shoal of 6+ or it gets stressed and nippy.
- Glowlight Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Gold Tetra✅ CompatiblePeaceful · 4.5 cm · Easy care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Gold Tetra in a shoal of 6+ or it gets stressed and nippy.
- Golden Dwarf Barb✅ CompatiblePeaceful · 4 cm · Easy care · 18–24 °C (64–75 °F)
- Compatible on the things that matter: shared water near 22–24 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Golden Dwarf Barb in a shoal of 6+ or it gets stressed and nippy.
- Jelly Bean Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 20–26 °C (68–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Jelly Bean Tetra in a shoal of 10+ or it gets stressed and nippy.
- Marbled Hatchetfish✅ CompatiblePeaceful · 4 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Otocinclus✅ CompatiblePeaceful · 4 cm · Medium care · 21–26 °C (70–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Otocinclus in a shoal of 6+ or it gets stressed and nippy.
- Phoenix Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
- Purple Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 22–26 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Purple Tetra in a shoal of 8+ or it gets stressed and nippy.
- Rainbow Emperor Tetra✅ CompatibleSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 22–28 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
- Rosy Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Rosy Tetra in a shoal of 6+ or it gets stressed and nippy.
- Rummy Nose Rasbora✅ CompatiblePeaceful · 4 cm · Medium care · 20–26 °C (68–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Rummy Nose Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Sparkling Gourami✅ CompatiblePeaceful · 4 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.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Strawberry Betta✅ CompatiblePeaceful · 4 cm · Medium care · 22–27 °C (72–81 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Threadfin Rainbowfish✅ CompatiblePeaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Threadfin Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Tiger Otocinclus✅ CompatiblePeaceful · 4 cm · Medium care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Tiger Otocinclus in a shoal of 6+ or it gets stressed and nippy.
- Yellow Phantom Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–27 °C (73–81 °F)
- Both are peaceful, and their water overlaps around 23–27 °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 Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Yellow Phantom Tetra in a shoal of 6+ or it gets stressed and nippy.
- Black Darter Tetra⚠️ With cautionSemi-aggressive · 4 cm · Hard care · 21–28 °C (70–82 °F)
- Expect Black Darter Tetra to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom 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 and Red Phantom Tetra are close in size, but the semi-aggressive one tends to dominate — add red phantom tetra in a group to spread the pressure.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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)
- Black Skirt Tetra is semi-aggressive and may chase or nip the smaller Red Phantom Tetra — plant heavily and break up sight lines.
- Keep Red Phantom 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.
- Cherry Shrimp⚠️ With cautionPeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Red Phantom Tetra may eat Cherry Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Cherry Shrimp in a shoal of 10+ 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 Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom 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 Red Phantom 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.
- Ghost Shrimp⚠️ With cautionPeaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
- Red Phantom Tetra may eat Ghost Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Ghost Shrimp 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 is semi-aggressive and may chase or nip the smaller Red Phantom Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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 Red Phantom 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.
- Serpae Tetra⚠️ With cautionSemi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Expect Serpae Tetra to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Serpae Tetra in a shoal of 6+ or it gets stressed and nippy.
- Silvertip Tetra⚠️ With cautionSemi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Expect Silvertip Tetra to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom 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)
- Expect Spotfin Betta to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom 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 Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Tiger Badis⚠️ With cautionSemi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
- Expect Tiger Badis to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Tiger Shrimp⚠️ With cautionPeaceful · 3 cm · Hard care · 20–25 °C (68–77 °F)
- Red Phantom Tetra may eat Tiger Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Tiger Shrimp in a shoal of 6+ 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 Red Phantom Tetra — plant heavily and break up sight lines.
- Keep Red Phantom 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)
- Alligator Gar (250 cm) is big enough to swallow the 4 cm Red Phantom Tetra whole.
- Expect Alligator Gar to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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)
- Red Phantom Tetra is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
- Expect Clown Knifefish to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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)
- Size gap is too large (100 vs 4 cm): Fire Eel will treat Red Phantom Tetra as food.
- Fire Eel clearly outsizes Red Phantom 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 Red Phantom 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)
- Red Phantom Tetra is bite-sized to a 90 cm koi — it will be eaten.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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)
- Redtail Catfish (120 cm) is big enough to swallow the 4 cm Red Phantom Tetra whole.
- Redtail Catfish is aggressive and may chase or nip the smaller Red Phantom 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 Red Phantom 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)
- Spotted Gar (90 cm) is big enough to swallow the 4 cm Red Phantom Tetra whole.
- Spotted Gar is aggressive and may chase or nip the smaller Red Phantom Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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)
- Red Phantom Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Expect Wels Catfish to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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)
- Wolf Cichlid (72 cm) is big enough to swallow the 4 cm Red Phantom Tetra whole.
- Expect Wolf Cichlid to harass Red Phantom Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Red Phantom 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.
Red Phantom Tetra care specs
- Care level
- Easy
- Breeding
- Medium
- Max size
- 4 cm (1.6 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 5.5–7.5
- Hardness
- 2–12 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Characidae
- Origin
- South America — upper and middle Orinoco basin, Colombia and Venezuela
What is a Red Phantom Tetra?
The Red Phantom Tetra (Hyphessobrycon sweglesi) is a compact, vividly coloured characin from the blackwaters of South America that reaches roughly 4 cm (1.6 in) as an adult. Males carry a deep crimson body with a bold black shoulder spot and flag-like extensions on the dorsal and anal fins. A school of males under warm, angled light in a dark, heavily planted aquarium is among the more striking sights in freshwater fishkeeping.
Females are slightly stouter and carry a distinctive white spot on the dorsal fin, making sexing straightforward. Despite its showiness, the Red Phantom is an unpretentious community fish: peaceful, hardy once settled, and tolerant of a wide enough water-chemistry range to fit most soft-to-moderate-hardness community setups.
Where do Red Phantom Tetras come from and what is their natural habitat?
Wild Red Phantom Tetras inhabit the upper and middle Orinoco basin in Colombia and Venezuela, in slow-moving, deeply shaded blackwater and clearwater streams. The water is warm, very soft and acidic, stained brown with tannins from leaf litter and submerged wood, and dimmed by dense overhanging vegetation.
This habitat is low in dissolved minerals and free of strong current. Understanding that origin explains almost everything about good care: the species thrives in soft, slightly acidic, tannin-rich water with subdued lighting, and tends to lose colour and become prone to stress when kept hard and alkaline under bright illumination. Captive-bred stock is modestly more adaptable than wild-caught, but the preference remains.
What tank size and setup does a Red Phantom Tetra need?
The practical minimum is 60 litres (16 gal) — enough volume for a stable school of eight or more and the biological filtration to support them. A long, lower-profile footprint (such as 60 × 30 cm / 24 × 12 in or larger) is preferable to a tall, narrow tank, since Red Phantoms are mid-column swimmers that use horizontal space more than vertical height.
For decor, lean into the blackwater aesthetic: a dark substrate (fine black sand works well), driftwood and twisted roots, Indian almond leaves or oak leaves on the bottom, and dense planting with softer species such as Java fern, Bolbitis, Vallisneria or floating plants that diffuse the light. A dark background completes the effect and makes the fish’s red pop against it. Gentle filtration — sponge filters or a low-flow HOB turned to its quietest setting — is preferred; strong current is unnatural for this species. The tank should be covered, as most tetras are capable jumpers.
What water parameters do Red Phantom Tetras need?
- Temperature: 22–28 °C (72–82 °F) — the upper part of that range, around 24–26 °C (75–79 °F), is the sweet spot for long-term colour and activity.
- pH: 5.5–7.5; colour and health are best between 6.0 and 7.0.
- Hardness: 2–12 dGH. Soft water (2–8 dGH) consistently produces the richest red; harder water does not harm them but does mute the colouration.
As with all smaller tetras, stability is more important than hitting exact numbers. Cycle the tank fully before adding fish, perform regular partial water changes (25–30% weekly), and avoid sudden chemistry swings. If your tap water is hard and alkaline, reverse-osmosis water blended with tap to reach target parameters is a straightforward fix.
What do Red Phantom Tetras eat?
Red Phantoms are omnivores, picking off small invertebrates and organic particles in the wild. In captivity they accept food readily: a quality small-pellet or micro-crumble staple provides the nutritional base, and rotating in frozen or live foods — daphnia, baby brine shrimp and small bloodworms — drives up colour intensity and encourages natural foraging behaviour.
Feed small amounts once or twice daily, only what the fish consume within two minutes. Uneaten food in a soft-water tank degrades quality quickly. A once-weekly fast day is a simple preventive measure.
How do Red Phantom Tetras behave, and what fish can live with them?
Red Phantoms are peaceful schooling fish that spend most of their time in the middle of the water column, moving in a loose but coherent group. Kept in groups below six they become noticeably skittish and occasionally nippy; in groups of eight or more — ideally ten or twelve — the internal social dynamic settles into the relaxed, display-driven behaviour the species is known for.
They are compatible with a wide range of soft-water community fish: other small tetras (Black Phantom, Ember Tetra, Cardinal Tetra), pencilfish, Apistogramma pairs, small Corydoras and peaceful dwarf cichlids all coexist well. Avoid boisterous or aggressive species that will outcompete them for food or harass their fins. Shrimp can be kept with adults in well-planted tanks, though very small shrimp fry may not survive.
For a full, filterable list of species that work — and those that don’t — see Red Phantom Tetra tank mates.
How do you tell male from female Red Phantom Tetras?
Sexing adults is straightforward. Males are slimmer, more intensely red, and develop noticeably elongated, flag-like extensions on the dorsal and anal fins — in peak condition often edged with black. Females are fuller-bodied (especially when carrying eggs), moderately red to orange-red, and display a small but distinct white spot on the dorsal fin. The white spot is the fastest identification shortcut and visible even in younger fish approaching maturity.
How do Red Phantom Tetras breed?
Red Phantoms are egg-scattering, open-water spawners. Conditioning a pair or a group (one male, two females) on live and frozen foods for a week or two raises the likelihood of spawning. A separate breeding tank of 20–40 L (5–10 gal) with very soft, slightly acidic water (pH 6.0–6.5, under 4 dGH), dim lighting and a fine-leaved plant such as Java moss or a spawning mop as an egg receptacle is the standard approach.
The male courts the female with spreading fin displays; spawning is brief and produces a scatter of small, adhesive eggs. Adults will eat the eggs if left in the tank, so remove the parents after spawning is observed. Eggs hatch in roughly 24–36 hours and the fry are free-swimming within 3–5 days. Infusoria or commercial fry foods are needed for the first week; freshly hatched brine shrimp can be introduced from day 5–7 onwards. We rate breeding at medium difficulty — achievable for a patient intermediate keeper but not casually self-sustaining.
What diseases are common in Red Phantom Tetras, and how do you prevent them?
The diseases most likely to affect this species are the usual small-tetra suspects: Ich (white pin-head spots), Velvet (a dusty gold sheen under raking light), fin rot (ragged, receding fin edges), and Neon Tetra Disease (Pleistophora hyphessobryconis), which causes patchy colour loss and body wasting with no effective cure. All are strongly linked to poor water quality, sudden parameter swings or unquarantined new arrivals.
Prevention: maintain a cycled tank, keep water changes consistent, avoid temperature swings, quarantine new fish 2–4 weeks before mixing them in, and keep the school at eight or more to minimise social stress.
Health note: disease identification and medication dosing are outside the scope of this care profile. If your fish show persistent symptoms, compare them against a reputable veterinary or aquarium-health resource before treating, and treat the water first.
How long do Red Phantom Tetras live?
In a well-maintained aquarium, Red Phantom Tetras live 3–5 years. Fish sold in stores are typically a few months old, so most of that range is still ahead of them. Stable soft water, the right temperature, a school of eight or more, and a varied diet are the four pillars of longevity. Males tend to show their best colour from the second year onward, so the investment pays off visually over time.
Frequently asked questions
What is the difference between Red Phantom and Black Phantom tetras?
The Red Phantom (*Hyphessobrycon sweglesi*) is a rich crimson-red with a dark shoulder spot and comes from the Orinoco; the Black Phantom (*Megalamphodus megalopterus*) is a silvery-grey with a black shoulder blotch and originates from the Paraguay basin. Both share similar care needs and make excellent companions in the same soft-water tank.
Why do my Red Phantom Tetras nip fins?
Fin-nipping in this species is almost always a group-size issue. In groups of fewer than six, the fish become stressed and redirect aggression outward. Keep at least eight — ideally ten or more — and nipping behaviour typically disappears as the school's internal social dynamic stabilises.
What you need to keep a red phantom tetra
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a red phantom tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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