Photo: Chronotopian (CC BY-SA 3.0) — via Wikimedia Commons
Glass Bloodfin Tetra (Prionobrama filigera)
A crystal-bodied schooling tetra with vivid red fins — effortlessly elegant and one of the easiest South American characins to keep.
Will it live with a Glass Bloodfin Tetra?
We compare each fish against your glass bloodfin 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)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Adolf's Cory in a shoal of 6+ or it gets stressed and nippy.
- Agassiz's Corydoras✅ CompatiblePeaceful · 6 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.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Blackline Rasbora✅ CompatiblePeaceful · 6 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Blackline Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Blood Red Tiger Pleco✅ CompatiblePeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Glass Bloodfin Tetra 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)
- 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Butterfly Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–24 °C (64–75 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Corydoras Catfish✅ CompatiblePeaceful · 6.5 cm · Easy 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Corydoras Catfish in a shoal of 6+ or it gets stressed and nippy.
- Diamond Tetra✅ CompatiblePeaceful · 6 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
- Duplicareus Corydoras✅ CompatiblePeaceful · 5.5 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.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Duplicareus Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Elegant Cory✅ CompatiblePeaceful · 6 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.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Elegant Cory in a shoal of 6+ or it gets stressed and nippy.
- False Julii Corydoras✅ CompatiblePeaceful · 6 cm · Easy 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep False Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
- German Blue Ram✅ CompatiblePeaceful · 6 cm · Hard care · 27–30 °C (81–86 °F)
- Both are peaceful, and their water overlaps around 27–28 °C — no size, zone or temperament conflicts.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Guppy✅ CompatiblePeaceful · 6 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.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 20–24 °C (68–75 °F)
- Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Narcissus II 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Narcissus II Cory in a shoal of 6+ or it gets stressed and nippy.
- Neon Dwarf Rainbowfish✅ CompatiblePeaceful · 6 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Neon Dwarf Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Panda Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–23 °C (64–73 °F)
- Both are peaceful, and their water overlaps around 22–23 °C — no size, zone or temperament conflicts.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Pearl Danio✅ CompatiblePeaceful · 6 cm · Easy care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Pearl Danio in a shoal of 6+ or it gets stressed and nippy.
- Platy✅ CompatiblePeaceful · 6 cm · Easy care · 21–28 °C (70–82 °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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Rust Corydoras✅ CompatiblePeaceful · 5.5 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.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Rust Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Samurai Gourami✅ CompatiblePeaceful · 6 cm · Hard 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.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Slate Corydoras✅ CompatiblePeaceful · 6 cm · Medium 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Slate Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Corydoras✅ CompatiblePeaceful · 6.5 cm · Easy 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Spotfin Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Sterbai Corydoras✅ CompatiblePeaceful · 6.5 cm · Medium care · 24–30 °C (75–86 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Sterbai Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Ash Lipped Apisto⚠️ With cautionSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Ash Lipped Apisto is semi-aggressive and may chase or nip the smaller Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Banded Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Banded Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Betta⚠️ With cautionSemi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
- Betta and Glass Bloodfin Tetra are close in size, but the semi-aggressive one tends to dominate — add glass bloodfin tetra in a group to spread the pressure.
- Keep Glass Bloodfin Tetra in a shoal of 6+ 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 Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ 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 Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Expect Bleeding Heart Tetra to harass Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bright Diamond Tetra⚠️ With cautionPeaceful · 7 cm · Hard care · 24–28 °C (75–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
- Colombian Tetra⚠️ With cautionSemi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
- Colombian Tetra is semi-aggressive and may chase or nip the smaller Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Colombian Tetra 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)
- Desert Goby is semi-aggressive and may chase or nip the smaller Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Keep Glass Bloodfin Tetra in a shoal of 6+ 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 Glass Bloodfin Tetra in a shoal of 6+ 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 Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- Expect GloFish Tetra to harass Glass Bloodfin Tetra at times; give dense cover and watch them at feeding.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep GloFish Tetra 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 Glass Bloodfin Tetra at times; give dense cover and watch them at feeding.
- Keep Glass Bloodfin Tetra in a shoal of 6+ 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)
- Expect Peaceful Betta to harass Glass Bloodfin Tetra at times; give dense cover and watch them at feeding.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Smaragd Betta⚠️ With cautionAggressive · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Smaragd Betta is aggressive and may chase or nip the smaller Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Three-striped Dwarf Cichlid⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 23–29 °C (73–84 °F)
- Expect Three-striped Dwarf Cichlid to harass Glass Bloodfin Tetra at times; give dense cover and watch them at feeding.
- Keep Glass Bloodfin Tetra in a shoal of 6+ 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 6 cm): Alligator Gar will treat Glass Bloodfin Tetra as food.
- Alligator Gar is aggressive and may chase or nip the smaller Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ 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 6 cm): Clown Knifefish will treat Glass Bloodfin Tetra as food.
- Expect Clown Knifefish to harass Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Fire Eel (100 cm) is big enough to swallow the 6 cm Glass Bloodfin Tetra whole.
- Fire Eel is semi-aggressive and may chase or nip the smaller Glass Bloodfin Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ 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 6 cm Glass Bloodfin Tetra whole.
- Redtail Catfish is aggressive and may chase or nip the smaller Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Size gap is too large (90 vs 6 cm): Spotted Gar will treat Glass Bloodfin Tetra as food.
- Spotted Gar is aggressive and may chase or nip the smaller Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Size gap is too large (300 vs 6 cm): Wels Catfish will treat Glass Bloodfin Tetra as food.
- Wels Catfish clearly outsizes Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ 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 6 cm Glass Bloodfin Tetra whole.
- Expect Wolf Cichlid to harass Glass Bloodfin 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 Glass Bloodfin Tetra in a shoal of 6+ 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.
Glass Bloodfin Tetra care specs
- Care level
- Easy
- Breeding
- Hard
- Max size
- 6 cm (2.4 in)
- Min tank size
- 75 L (19.8 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 6–7.5
- Hardness
- 2–15 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 6+ (shoaling)
- Family
- Characidae
- Origin
- South America — Rio Guaporé and Rio Paraguay basins, Bolivia and Brazil
What is a Glass Bloodfin Tetra?
The glass bloodfin tetra (Prionobrama filigera) is a slender, torpedo-shaped characin that reaches around 6 cm (2.4 in) in length at maturity. It belongs to the family Characidae — the same broad group that contains neon tetras, rummy-nose tetras and cardinal tetras — and shares the active, mid-water schooling habits common to the family. What sets it apart is its body: the flanks are almost entirely transparent, giving the impression of a living glass tube with vivid red pigment concentrated in the tail, anal fin, and dorsal fin. Under aquarium lighting with a dark substrate, that colour appears to float independently of the body, making a school of eight or ten fish genuinely eye-catching.
Despite its delicate appearance, the glass bloodfin is hardy and forgiving. It tolerates a wide range of water conditions, accepts dry foods readily, and integrates smoothly into most peaceful community set-ups. Experienced aquarists sometimes overlook it in favour of flashier species; that is a mistake. For adult fishkeepers who want low-maintenance elegance and constant mid-water movement, Prionobrama filigera is one of the more satisfying choices in the hobby.
Where do glass bloodfin tetras come from?
Glass bloodfin tetras are native to South America, specifically the Rio Guaporé and Rio Paraguay drainage basins spanning parts of Bolivia and Brazil. These rivers and their tributaries flow through seasonally flooded lowland forests and open savannahs (the cerrado). The water is typically warm, soft to moderately hard, and slightly acidic to neutral — stained pale amber in forested stretches by tannins from leaf litter and submerged wood, but often clearer in open-channel reaches.
Wild populations occupy the middle and upper water column, schooling in open water where they feed opportunistically on small invertebrates, surface insects, and plant matter drifting in the current. Understanding this origin informs everything about keeping the species well: they want warmth, reasonable water quality, gentle to moderate flow, and enough open swimming space to form and move as a cohesive school.
What tank size and setup do glass bloodfin tetras need?
A minimum of 75 L (20 gal) is required to house a school of six comfortably, and that size should be treated as a true floor rather than a comfortable target. A longer footprint — 80 cm (31 in) or more — suits a horizontal swimmer far better than a tall, narrow tank. Glass bloodfin tetras patrol the mid-water in tight formation and need length to do it properly.
For the best results, furnish the tank with:
- Dark substrate (fine dark sand or small-grain gravel) to reflect the fish’s colouration and encourage bolder behaviour.
- Driftwood and leaf litter to lend a soft, South American character and release mild tannins that bring pH gently toward the lower end of the species’ range.
- Floating or stem plants (such as Amazon frogbit, hornwort, or Water Sprite) to diffuse overhead light and provide a sense of security without blocking mid-water swimming lanes.
- Gentle to moderate filtration: a sponge filter or a spray-bar return turned toward the glass suits the species well. A powerful direct current disrupts schooling and adds stress.
A secure, close-fitting lid with no large gaps is non-negotiable — glass bloodfin tetras are confirmed jumpers, and a startled fish will find any gap.
What water parameters do glass bloodfin tetras need?
Glass bloodfin tetras are adaptable by tetra standards, but staying within their natural range will keep them visibly healthier and more colourful.
- Temperature: 22–28 °C (72–82 °F). They tolerate the cooler end of this range better than most tropical tetras, making them compatible with a wider array of tank-mates.
- pH: 6.0–7.5. Neutral water is fine; slightly acidic (6.5–7.0) tends to bring out the best colouration and supports natural behaviour.
- Hardness: 2–15 dGH. Soft to moderately hard water is acceptable; very hard, alkaline tap water should be mixed with RO or soft water if it falls outside the stated range.
Stability is more important than precision. A cycled tank with weekly water changes of 25–30% and no sudden temperature swings will produce far better outcomes than chasing exact numbers in an unstable system.
What do glass bloodfin tetras eat?
Glass bloodfin tetras are omnivores with a bias toward small animal matter, reflecting what wild fish encounter in their native rivers. In the aquarium they accept a wide range of foods readily:
- Staple dry food: quality micro-pellets or small tropical flakes form a practical daily base. Choose a product with a protein content of around 40% or higher.
- Frozen and live foods: bloodworms, daphnia, artemia (brine shrimp), and mosquito larvae trigger strong feeding responses and help maintain the brightness of the red finnage. Rotate these in three or four times a week.
- Vegetable matter: they will graze on algae wafers or accept blanched spinach, though this is secondary to protein.
Feed small amounts once or twice daily — what the fish consume in two to three minutes. Excess food that reaches the substrate degrades water quality faster than almost anything else in a small-to-medium tank.
How do glass bloodfin tetras behave, and what fish can live with them?
Glass bloodfin tetras are peaceful and thoroughly social within their own school. In groups of six or fewer, individuals become nervous, tend to hide at tank edges, and often show paler colouration. In a school of eight to ten or more, the transformation is immediate: the fish move confidently in coordinated formation, feed more aggressively, and display full colour. Getting the school size right is the single most impactful husbandry decision for this species.
Because they occupy the middle water column, they pair naturally with species that use other tank zones: small corydoras or otocinclus on the bottom, peaceful dwarf gouramis or small rasboras at the surface. Avoid large, boisterous, or predatory species — anything with a mouth big enough to swallow a 6 cm fish is a risk. Fin-nipping species (tiger barbs, serpae tetras) should also be avoided; the glass bloodfin’s flowing caudal fin is a tempting target.
For a full list of tested pairings, see Glass Bloodfin Tetra tank mates.
How do you tell male from female glass bloodfin tetras?
Sexual dimorphism in Prionobrama filigera is present but subtle, and reliably visible only in well-conditioned adult fish:
- Females are noticeably fuller-bodied, particularly across the belly when viewed from above or from the side. A ripe female ready to spawn will appear distinctly rounder than any male of comparable length.
- Males are slimmer and more streamlined. Some reports indicate that males show a slightly more intense red colouration in the caudal fin, though this varies with condition and lighting.
In a mixed school of healthy adults, the belly-depth difference is the most reliable indicator. Juveniles are effectively unsexable until they begin to mature at around six to eight months of age.
How do you breed glass bloodfin tetras?
Breeding glass bloodfin tetras is rated Hard and is not a project for beginners, despite the species being easy to keep in a community setting. The difficulty lies in triggering spawning reliably, protecting the eggs from adult consumption, and raising the fry through their most fragile early stages.
Conditioning: Separate a small group of well-conditioned adults — ideally two or three pairs — and feed them heavily on live or frozen foods for two to three weeks. A dedicated breeding tank of 30–40 L with soft, slightly acidic water (pH 6.2–6.8, very soft), fine-leaved plants such as Java moss or spawning mops, and no substrate is the typical set-up.
Spawning: Glass bloodfin tetras are egg-scatterers. They release small, adhesive eggs among fine-leaved plants. Adults will eat eggs immediately given the chance; remove the adults as soon as spawning is observed, or use a mesh barrier that lets eggs fall through but blocks adult access.
Fry: Eggs hatch in approximately 24–36 hours at 26–27 °C (79–81 °F). Fry are initially very small and require infusoria or commercial fry food for the first week before graduating to baby brine shrimp. Keep the breeding tank dimly lit and perform small daily water changes with matched-temperature water.
Success in captivity is documented but uncommon in hobby literature, and is largely the domain of specialist breeders.
What diseases commonly affect glass bloodfin tetras?
Glass bloodfin tetras are not unusually disease-prone, and the majority of health problems trace back to water quality or stress rather than to species-specific vulnerabilities.
Ich (white spot disease): Small white cysts on fins and body, caused by Ichthyophthirius multifiliis. Almost always triggered by chilling (a temperature drop outside the 22–28 °C range) or stress from overcrowding or a new introduction. Raising the tank temperature and improving conditions is the first intervention.
Fin rot: Fraying or receding fin edges caused by opportunistic bacteria or fungi. Almost invariably a secondary consequence of poor water quality, physical damage (fin-nipping), or chronic stress. Fixing the root cause and maintaining clean water is the primary response.
Velvet: A gold or rust-coloured dusty sheen on the body, caused by Oodinium parasites. Less common than ich but progresses quickly. Dim tank lighting and quarantine of affected fish are the first steps.
Neon tetra disease: Though more associated with closely related species, any unusual wasting, colour loss, or lumpy musculature in a group warrants attention and quarantine of affected individuals.
Prevention is straightforward: a cycled, stable tank; consistent temperature within range; regular water changes; and a two-to-four-week quarantine of all new fish and plants before introduction to the main display.
Health note: Medication dosing and definitive disease diagnosis are beyond the scope of a care profile. For sick fish, confirm symptoms against a reputable veterinary or fish-health resource before medicating — and address water quality first in almost every case.
How long do glass bloodfin tetras live?
With good husbandry, glass bloodfin tetras live 3–5 years in captivity. Fish purchased from reputable aquarium stores are generally young adults of six to twelve months, so with a healthy start and consistent care they should give three or more years of display life. The most common reasons for shortened lifespan are chronic low-grade water quality issues, under-sized schools causing long-term stress, and temperatures held at the low end of the range. Keep the tank stable, the school large, and the water clean, and this is a species that rewards its keeper with years of elegant, effortless movement through the mid-water.
Frequently asked questions
How many glass bloodfin tetras should I keep together?
A minimum of six is strongly recommended. This is a true schooling species that becomes visibly stressed in small groups — it is bolder, more active and shows far better colour in a tight school of eight or more.
Can glass bloodfin tetras jump?
Yes, they are active, strong swimmers and known jumpers. A well-fitting lid with no large gaps is essential; even a small opening is enough for a spooked fish to escape overnight.
What you need to keep a glass bloodfin tetra
The baseline is a heated, filtered 75 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a glass bloodfin tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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