Photo: D. Bork and A. Zarske (CC BY 4.0) — via Wikimedia Commons
Phoenix Tetra (Hemigrammus filamentosus)
A dazzling small tetra with flaming red fins tipped in white — peaceful, active, and ideal for soft-water planted tanks.
Will it live with a Phoenix Tetra?
We compare each fish against your phoenix 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, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Phoenix 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 Phoenix 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 Phoenix 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 Phoenix 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, 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 Phoenix 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 Phoenix 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)
- Compatible on the things that matter: shared water near 23–27 °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 Phoenix 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; 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 Phoenix 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)
- 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 Phoenix 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)
- 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 Phoenix 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 23–24 °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 Phoenix 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; 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 Phoenix 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 Phoenix 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 Phoenix 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.
- Purple Tetra✅ 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.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Phoenix 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; 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 Phoenix 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.
- Red Phantom Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °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 Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
- Keep Red Phantom 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; 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 Phoenix 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 23–26 °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 Phoenix 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 Phoenix 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 Phoenix 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, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Phoenix 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)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Phoenix 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)
- Compatible on the things that matter: shared water near 23–27 °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 Phoenix 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 Phoenix Tetra at times; give dense cover and watch them at feeding.
- Keep Phoenix 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 Phoenix Tetra are close in size, but the semi-aggressive one tends to dominate — add phoenix 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 Phoenix 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 Phoenix Tetra — plant heavily and break up sight lines.
- Keep Phoenix 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.
- Blue Turbo Snail⚠️ With cautionPeaceful · 5 cm · Medium care · 25–30 °C (77–86 °F)
- pH preferences only just meet (Phoenix Tetra 6–7 vs Blue Turbo Snail 7.5–8.5) — target the overlap and acclimate slowly.
- Keep Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
- Cherry Shrimp⚠️ With cautionPeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Phoenix Tetra may eat Cherry Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Phoenix 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)
- Desert Goby and Phoenix Tetra are close in size, but the semi-aggressive one tends to dominate — add phoenix tetra in a group to spread the pressure.
- Keep Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
- Ghost Shrimp⚠️ With cautionPeaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
- Phoenix Tetra may eat Ghost Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Phoenix 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)
- Expect Humpbacked Tetra to harass Phoenix Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Phoenix 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 Phoenix 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 Phoenix Tetra at times; give dense cover and watch them at feeding.
- Keep Phoenix 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 Phoenix Tetra at times; give dense cover and watch them at feeding.
- Keep Phoenix 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 and Phoenix Tetra are close in size, but the semi-aggressive one tends to dominate — add phoenix tetra in a group to spread the pressure.
- Keep Phoenix 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 Phoenix Tetra at times; give dense cover and watch them at feeding.
- Keep Phoenix 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)
- Tiger Badis is semi-aggressive and may chase or nip the smaller Phoenix Tetra — plant heavily and break up sight lines.
- Keep Phoenix 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)
- Phoenix Tetra may eat Tiger Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Phoenix 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 Phoenix Tetra — plant heavily and break up sight lines.
- Keep Phoenix 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)
- Phoenix Tetra is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
- Alligator Gar clearly outsizes Phoenix Tetra and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Phoenix 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)
- Clown Knifefish (90 cm) is big enough to swallow the 4 cm Phoenix Tetra whole.
- Expect Clown Knifefish to harass Phoenix 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 Phoenix 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 Phoenix Tetra as food.
- Expect Fire Eel to harass Phoenix Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Phoenix 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 4 cm Phoenix Tetra whole.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Phoenix 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 Phoenix Tetra whole.
- Redtail Catfish is aggressive and may chase or nip the smaller Phoenix 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 Phoenix 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 Phoenix Tetra whole.
- Expect Spotted Gar to harass Phoenix 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 Phoenix 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)
- Wels Catfish (300 cm) is big enough to swallow the 4 cm Phoenix Tetra whole.
- Wels Catfish clearly outsizes Phoenix Tetra and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Phoenix 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)
- Phoenix 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 Phoenix 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 Phoenix 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.
Phoenix Tetra care specs
- Care level
- Easy
- Breeding
- Hard
- Max size
- 4 cm (1.6 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 23–28 °C (73–82 °F)
- pH
- 6–7
- Hardness
- 1–10 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Acestrorhamphidae
- Origin
- South America — Rio Araguaia basin, Brazil
What is a Phoenix Tetra?
The Phoenix Tetra (Hemigrammus filamentosus) is a small South American characin scientifically described in 2011 from the Rio Araguaia basin of Brazil. Reaching 4 cm (1.6 in), it is compact even by tetra standards, but its colour more than compensates: the body is a silver-grey overlaid with a faint gold sheen while the dorsal, anal and pelvic fins carry deep red that fades to elongated white filament tips — the trait behind both its scientific name and its common one. In a planted tank against dark substrate, a school in full colour is among the more striking displays the characin family offers. Tank-bred stock is increasingly available from specialist retailers, making it a more sustainable choice than wild-caught imports.
Where do Phoenix Tetras come from?
Wild Phoenix Tetras inhabit the Rio Araguaia basin in central Brazil, a major Amazon tributary system. The Araguaia’s igapós (seasonally flooded forest margins) are classic blackwater environments: water stained tea-brown by leaf litter, low pH, minimal hardness and dim, scattered light filtering through the canopy. Submerged roots, leaf beds and aquatic vegetation provide the dense cover where small characins school for safety. Every element of good husbandry — soft acidic water, subdued lighting, botanical decor — mirrors those natural conditions directly.
What size tank does a Phoenix Tetra need, and how should it be set up?
A minimum of 60 litres (16 gallons) is the practical baseline, and that assumes you are keeping the recommended minimum group of eight. A 75–90 L (20–24 gal) tank is more comfortable and gives a larger school of ten to twelve room to shoal properly across the middle column.
Phoenix Tetras respond strongly to a well-considered aquascape:
- Substrate: Fine dark sand. Dark colour grounds the fish and intensifies their red pigment; pale gravel washes them out.
- Lighting: Low to moderate. Use floating plants (salvinia, frogbit) or heavily leaved background plants to diffuse the beam. Tannins from Indian almond leaves or alder cones further soften light and condition water.
- Decor: Driftwood, twisted roots and a bed of dried leaves on the substrate create both visual security and a more authentic habitat. Leaf litter also releases beneficial humic acids.
- Filtration: Gentle is essential. A sponge filter or an adjustable hang-on-back turned to low output prevents fin stress and keeps the current soft enough for comfortable schooling.
What water parameters do Phoenix Tetras need?
The 16-field quick-facts tell the story clearly:
- Temperature: 23–28 °C (73–82 °F). They tolerate the lower end but thrive and show the best colour in the mid-range, around 25–27 °C (77–81 °F).
- pH: 6.0–7.0. Soft, slightly acidic water is ideal; avoid anything alkaline.
- Hardness: 1–10 dGH. Very soft water is natural for this species. Hard tap water above 10 dGH should be cut with RO water.
Stability matters as much as target numbers. Cycle the tank fully before adding fish, perform 25–30 % water changes weekly, and avoid sudden swings. Phoenix Tetras are sensitive to ammonia and nitrite; a mature filter is non-negotiable. A weekly parameter check prevents most problems before they develop.
What do Phoenix Tetras eat?
Phoenix Tetras are omnivores with no unusual dietary demands. A quality micro-pellet or fine flake staple covers the basics, but fins and colour respond noticeably to variety. Supplement with:
- Frozen or live small invertebrates: daphnia, micro-worms, baby brine shrimp (nauplii) and mosquito larvae are all accepted greedily.
- Freeze-dried options: blackworms and bloodworms as occasional treats.
Feed once or twice a day in small amounts that are consumed within two minutes. Overfeeding degrades water quality rapidly in a softwater setup — the buffering capacity to absorb a spike is low. A one-day fast per week is good practice.
How do Phoenix Tetras behave, and what are good tank mates?
Phoenix Tetras are entirely peaceful and pose no threat to any fish too large to be swallowed. They are an active, tight-schooling species that spends the majority of its time in the middle column, occasionally venturing toward the surface or bottom. In groups of eight or more they form cohesive shoals and display confident, open-water behaviour; in smaller numbers they scatter, pale and spend most of their time hiding. Group size is the single biggest welfare lever you have with this species.
Ideal community partners share their soft-water chemistry requirements:
- Bottom level: Corydoras (small species like C. pygmaeus or C. habrosus), Otocinclus, dwarf loaches.
- Middle level: Other small characins (ember tetras, green neon tetras), small rasboras, pencilfish.
- Upper level: Hatchetfish.
- Specialty: Apistogramma and other dwarf cichlids that are not aggressive toward small open-water fish.
Avoid: Livebearers and goldfish (wrong chemistry), large or aggressive cichlids, any fish likely to nip fins, and species needing hard alkaline water.
For a full compatibility breakdown, see Phoenix Tetra tank mates.
How do you tell a male Phoenix Tetra from a female?
Sexing requires a close look at well-conditioned adults. Females are noticeably deeper-bodied, the difference becoming obvious in gravid fish — rounder from above and in profile. Males are slimmer with brighter, more saturated red fins and more elongated white filament tips on the dorsal and anal fins; the filament length is often the clearest single marker in a side-lit tank. Juveniles under 2 cm cannot be sexed reliably; wait until fish approach their adult 3–4 cm before making a call.
How do you breed Phoenix Tetras?
Breeding is rated Hard — a project for experienced fishkeepers, not a routine community-tank outcome. Like most characins, Phoenix Tetras scatter adhesive eggs among fine-leaved plants or spawning mops and provide no parental care; adults will eat eggs and fry immediately.
A dedicated 30–40 L (8–10 gal) tank is required: bare-bottom or mop-only, dimly lit, with very soft acidic water (pH 6.0–6.5, hardness below 5 dGH) and a sponge filter. Condition a pair or a group of two males to one female on live foods for one to two weeks. Spawning typically occurs at dawn; remove adults immediately afterward. Eggs hatch in roughly 24–36 hours at 26 °C (79 °F); fry start on infusoria or commercial first-fry foods before progressing to baby brine shrimp nauplii. Growth is slow and variable success rates account for the Hard rating.
What diseases are common in Phoenix Tetras?
Phoenix Tetras are not unusually disease-prone, but low pH and low hardness leave little chemical buffering to absorb problems, so issues escalate quickly. Common culprits:
- Ich (white spot): Tiny white dots, typically triggered by temperature drops or shipping stress. Prevent with a stable heater and a proper quarantine period.
- Velvet (Oodinium): A gold-dust sheen on the body, more common in soft-water blackwater species. Clean water and dim lighting are the primary deterrents.
- Fin rot: Fraying or receding fins almost always trace back to water quality or fin-nipping tank mates — fix the cause before anything else.
- Wasting: Failure to maintain weight despite eating can indicate internal parasites introduced through live food; use frozen alternatives where possible.
A cycled tank, weekly water changes and a two-to-four-week quarantine for all new arrivals prevent the overwhelming majority of problems.
Health note: Medication dosing and disease diagnosis are beyond the scope of a care profile. Confirm symptoms against a reputable aquatic-health source before medicating; soft, unbuffered water can make some treatments more potent than the label anticipates.
How long do Phoenix Tetras live?
Phoenix Tetras live 3–5 years under good conditions — typical for a small characin of this size. Tank-bred stock generally outlasts wild-caught imports because it arrives healthier and is already acclimated to aquarium life. Consistent soft-water chemistry, a varied diet and a large, stable group are the three factors most directly linked to reaching the upper end of that range.
Frequently asked questions
How many Phoenix Tetras should I keep together?
A minimum group of 8 is strongly recommended. Phoenix Tetras are a tight-schooling species and individuals kept in smaller numbers become stressed, pale and hide constantly. Larger groups of 12 or more produce the best colour and the most natural shoaling behaviour.
Are Phoenix Tetras suitable for a community tank?
Yes — they are entirely peaceful and safe with any fish too large to eat them. They do best with other soft-water species such as corydoras, dwarf cichlids, small rasboras and other characins. Avoid hard-water fish like livebearers and goldfish, as their chemistry needs are incompatible.
What you need to keep a phoenix tetra
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 23–28 °C (73–82 °F), a gentle filter that won't batter a phoenix tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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