Photo: Øyvind Holmstad (CC BY-SA 3.0) — via Wikimedia Commons
Buenos Aires Tetra (Hyphessobrycon anisitsi)
A bold, energetic schooling tetra from the Río de la Plata basin — colourful, hardy, and best kept away from live plants it will devour.
Will it live with a Buenos Aires Tetra?
We compare each fish against your buenos aires 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)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Buenos Aires 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)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Buenos Aires 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.
- Black Kuhli Loach✅ CompatiblePeaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Buenos Aires Tetra 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)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bolivian Ram✅ CompatiblePeaceful · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Brilliant Rasbora✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, 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 Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Brilliant Rasbora 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)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 18–24 °C — no size, zone or temperament conflicts.
- Keep Buenos Aires 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)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires 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.
- Duplicareus Corydoras✅ CompatiblePeaceful · 5.5 cm · Medium care · 23–27 °C (73–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Buenos Aires 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.
- Dwarf Chain Loach✅ CompatiblePeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Buenos Aires 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.
- Elegant Cory✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Buenos Aires 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)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Buenos Aires 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.
- Glass Catfish✅ CompatiblePeaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
- Semi-aggressive + Peaceful, 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 Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Gold Barb✅ CompatiblePeaceful · 7.5 cm · Easy care · 18–26 °C (64–79 °F)
- Semi-aggressive + Peaceful, 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 Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Gold Barb in a shoal of 6+ or it gets stressed and nippy.
- Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 20–24 °C (68–75 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 20–24 °C — no size, zone or temperament conflicts.
- Keep Buenos Aires 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)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires 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.
- Panda Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–23 °C (64–73 °F)
- Compatible on the things that matter: shared water near 18–23 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Peppered Corydoras✅ CompatiblePeaceful · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Compatible on the things that matter: shared water near 18–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Peppered Corydoras 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)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Buenos Aires 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.
- Slate Corydoras✅ CompatiblePeaceful · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires 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.
- Splashing Tetra✅ CompatiblePeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Splashing Tetra 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)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Buenos Aires 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.
- Spotted Corydoras✅ CompatiblePeaceful · 7 cm · Easy care · 22–27 °C (72–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Spotted 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 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Buenos Aires 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)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Keep Buenos Aires 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)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Keep Buenos Aires 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)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Keep Buenos Aires 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)
- Expect Buenos Aires Tetra to harass Bright Diamond Tetra at times; give dense cover and watch them at feeding.
- Keep Buenos Aires 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.
- Celebes Rainbowfish⚠️ With cautionPeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Buenos Aires Tetra is semi-aggressive and may chase or nip the smaller Celebes Rainbowfish — plant heavily and break up sight lines.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Costa's Tetra⚠️ With cautionPeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Buenos Aires Tetra is semi-aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
- Croaking Gourami⚠️ With cautionPeaceful · 7 cm · Easy care · 24–28 °C (75–82 °F)
- Buenos Aires Tetra and Croaking Gourami are close in size, but the semi-aggressive one tends to dominate — add croaking gourami in a group to spread the pressure.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Hongsloi Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 24–29 °C (75–84 °F)
- Buenos Aires Tetra and Hongsloi Dwarf Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Melon Barb⚠️ With cautionPeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Buenos Aires Tetra is semi-aggressive and may chase or nip the smaller Melon Barb — plant heavily and break up sight lines.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Melon Barb in a shoal of 8+ or it gets stressed and nippy.
- Peacock Gudgeon⚠️ With cautionPeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Buenos Aires Tetra is semi-aggressive and may chase or nip the smaller Peacock Gudgeon — plant heavily and break up sight lines.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Rio Negro Checkerboard Cichlid⚠️ With cautionPeaceful · 7 cm · Hard care · 24–29 °C (75–84 °F)
- One likes softer water and the other harder (5–15 vs 0–4 dGH) — a compromise, not a perfect match.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Rounded Filament Barb⚠️ With cautionPeaceful · 7 cm · Medium care · 22–27 °C (72–81 °F)
- Buenos Aires Tetra and Rounded Filament Barb are close in size, but the semi-aggressive one tends to dominate — add rounded filament barb in a group to spread the pressure.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Rounded Filament Barb in a shoal of 6+ or it gets stressed and nippy.
- Roundtail Paradise Fish⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 10–26 °C (50–79 °F)
- Buenos Aires Tetra and Roundtail Paradise Fish can both be territorial; doable with space and dense planting, but watch for chasing.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Sumo Loach⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 22–26 °C (72–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Tiger Barb⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Buenos Aires Tetra and Tiger Barb can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 80 L tank is below the ~95 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Barb in a shoal of 6+ or it gets stressed and nippy.
- Umbrella Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 20–26 °C (68–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Keep Buenos Aires 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)
- Buenos Aires Tetra and Alligator Gar are both territorial and at least one is outright aggressive — expect serious fighting.
- Alligator Gar (250 cm) is big enough to swallow the 7 cm Buenos Aires Tetra whole.
- Buenos Aires Tetra is a notorious fin-nipper — even though Alligator Gar is larger, an active shoal will harass its trailing fins. Only safe in a full group of 6+ with plenty of cover.
- Your 80 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Two assertive fish, one genuinely aggressive: Buenos Aires Tetra and Clown Knifefish will hold territory and clash.
- Clown Knifefish (90 cm) is big enough to swallow the 7 cm Buenos Aires Tetra whole.
- Your 80 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Size gap is too large (100 vs 7 cm): Fire Eel will treat Buenos Aires Tetra as food.
- Buenos Aires Tetra and Fire Eel can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 80 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Buenos Aires Tetra is bite-sized to a 90 cm koi — it will be eaten.
- Koi is slow and long-finned; a busy buenos aires tetra shoal tends to nip at it. Keep buenos aires tetra in a proper group of 6+ and watch them closely.
- Your 80 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Buenos Aires Tetra and Redtail Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
- Buenos Aires Tetra is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
- Your 80 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Buenos Aires Tetra and Spotted Gar are both territorial and at least one is outright aggressive — expect serious fighting.
- Size gap is too large (90 vs 7 cm): Spotted Gar will treat Buenos Aires Tetra as food.
- Buenos Aires Tetra is a notorious fin-nipper — even though Spotted Gar is larger, an active shoal will harass its trailing fins. Only safe in a full group of 6+ with plenty of cover.
- Your 80 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Buenos Aires Tetra and Wels Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
- Buenos Aires Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Your 80 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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)
- Two assertive fish, one genuinely aggressive: Buenos Aires Tetra and Wolf Cichlid will hold territory and clash.
- Buenos Aires Tetra is bite-sized to a 72 cm predatory wolf cichlid — it will be eaten.
- Wolf Cichlid is slow and long-finned; a busy buenos aires tetra shoal tends to nip at it. Keep buenos aires tetra in a proper group of 6+ and watch them closely.
- Your 80 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires 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.
Buenos Aires Tetra care specs
- Care level
- Easy
- Breeding
- Medium
- Max size
- 7 cm (2.8 in)
- Min tank size
- 80 L (21.1 gal)
- Temperature
- 18–26 °C (64–79 °F)
- pH
- 6–7.5
- Hardness
- 5–15 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 6+ (shoaling)
- Family
- Characidae
- Origin
- South America — Río de la Plata basin (Argentina, Paraguay, Brazil)
What is a Buenos Aires Tetra?
The Buenos Aires tetra (Hyphessobrycon anisitsi) is a large, active schooling fish from the Characidae family — the same broad family as neons and cardinals, but noticeably tougher and more boisterous than its more popular cousins. Adults reach 7 cm (2.75 in), making them considerably bigger than most tetras on the market. The body is silver with a striking splash of red on the dorsal and caudal fins, and a characteristic black spot sits just before the tail base, giving the fish an unmistakable silhouette under good light.
What sets the Buenos Aires tetra apart is its temperature tolerance. Unlike most tropical tetras that demand 24 °C or above, this species handles temperatures as low as 18 °C (64 °F) comfortably — making it one of the few colourful schoolers suited to an unheated or subtropical aquarium. It is classified as Easy care — hardy, unfussy about water chemistry within a reasonable range, and a reliable feeder — but two traits require forethought: it will destroy soft-leaved live plants, and it fin-nips when kept in too-small a group.
Where do Buenos Aires Tetras come from?
The Buenos Aires tetra is native to the Río de la Plata basin across Argentina, Paraguay and southern Brazil — large, relatively fast-moving rivers with cooler temperatures than the Amazonian drainages most aquarium fish hail from. The natural habitat tends toward moderate hardness and near-neutral pH, reflecting the region’s geology rather than the soft blackwater of the Amazon.
Wild fish shoal in open water, feeding opportunistically on insects, plant matter and small invertebrates. This origin explains the species’ defining traits: built for current, omnivorous enough to eat vegetation, and schooling by instinct.
What Tank Size and Setup Does a Buenos Aires Tetra Need?
The minimum sensible tank for a school of six is 80 litres (21 gal), and a larger tank — 120 L (32 gal) or more — gives the school real room to shoal and reduces territorial friction. A long footprint matters more than height; Buenos Aires tetras are strong swimmers that cruise the middle column and appreciate open water in front with some structure toward the back and sides.
For décor, hardscape is your friend. Because these fish will shred soft plants, stick to robust, unpalatable species: java fern, anubias, java moss and bolbitis are the go-to options. Rocks, driftwood and smooth substrate (fine gravel or sand) complete a natural-looking setup that the fish won’t dismantle overnight. Avoid delicate stem plants entirely.
Filtration should provide a gentle to moderate current — these fish come from flowing rivers and appreciate some water movement, but a powerhead blasting the tank is overkill. A canister or hang-on-back filter rated for the tank volume is ideal.
What Water Parameters Do Buenos Aires Tetras Need?
- Temperature: 18–26 °C (64–79 °F). This wide range is one of the species’ great practical advantages — a subtropical or unheated setup at 20–22 °C is perfectly fine.
- pH: 6.0–7.5. Near-neutral works well and matches typical tap water in most regions.
- Hardness: 5–15 dGH. Moderate hardness is ideal; both soft and moderately hard tap water are tolerated.
Stability beats precision. A cycled tank with 25–30% weekly water changes keeps parameters steady. Buenos Aires tetras tolerate minor fluctuations but do not do well in an uncycled tank where ammonia spikes.
What Do Buenos Aires Tetras Eat?
Buenos Aires tetras are omnivores with a healthy appetite. A quality flake or micro-pellet as the staple covers the nutritional base; supplement two to three times per week with frozen foods — bloodworms, brine shrimp and daphnia all bring out the best red colouration. Vegetable matter is accepted too: spirulina flake or blanched spinach reflects the species’ natural diet. Feed small amounts once or twice daily and only as much as the school clears in two to three minutes — overfeeding is the most common water-quality mistake with fast-eating, active fish.
Are Buenos Aires Tetras Aggressive — and What Fish Can Live With Them?
Buenos Aires tetras are rated semi-aggressive, expressed primarily as fin-nipping toward long-finned or slow-moving tank-mates. The main trigger is small group size — three or four bored fish start harassing neighbours. Keep six or more and the intra-school dynamic absorbs most of that energy.
Good tank-mates are similarly sized, robust, and short-finned: tiger barbs, odessa barbs, larger rasboras, gold barbs, weather loaches, paradise fish, rainbow fish and most corydoras all work well. Mid-sized cichlids like keyhole or rainbow cichlids are also viable. The cooler-water tolerance makes a subtropical community — pairing this tetra with weather loaches or gold barbs — a natural fit few other tetras can share.
Avoid angelfish, fancy guppies, bettas, long-finned mollies, or any fish with flowing finnage that makes an inviting target. Small nano-fish may also be harassed.
For a curated, filterable list of proven pairings, see Buenos Aires Tetra tank mates.
How Do You Tell Male from Female Buenos Aires Tetras?
Sexing Buenos Aires tetras is straightforward once the fish are mature. Females are noticeably larger and fuller-bodied, with a rounder belly that becomes especially visible when she is carrying eggs. Males are smaller and slimmer, but compensate with more intense red colouration in the dorsal and caudal fins — a well-conditioned male in good light is a noticeably more vivid fish.
In a mixed school, size is the easiest cue and colour confirms it. Young fish are harder to sex; wait until they are at least 3–4 months old.
How Do Buenos Aires Tetras Breed?
Buenos Aires tetras are egg scatterers that do not practice parental care. Spawning is not difficult to trigger but raising fry requires a deliberate setup — hence the Medium difficulty rating.
Condition a pair or small group on live and frozen foods for a week. Set up a separate breeding tank of around 30–40 L (8–10 gal) with soft, slightly acidic water (pH 6.0–6.5, around 22–24 °C / 72–75 °F), a sponge filter, and spawning mops or java moss across the bottom. The pair scatter adhesive eggs in the morning; remove the adults immediately or they will eat the eggs. Eggs hatch in 24–36 hours; fry become free-swimming within three to five days. Start them on infusoria or commercial fry food, graduating to baby brine shrimp as they grow.
What Diseases Are Common in Buenos Aires Tetras?
Buenos Aires tetras are hardy, but they share the usual vulnerabilities of community fish. The most likely problems are:
- Ich (white spot disease): Fine white dots across body and fins, introduced via unquarantined fish or plants. Quarantine all new additions for two to four weeks.
- Fin rot: Ragged or receding fin edges driven by poor water quality. Prevent by maintaining the nitrogen cycle and keeping up with water changes.
- Neon tetra disease / microsporidiosis: Rare in this species but possible in any tetra. Fading colour and wasting are the main signs; no reliable cure, so strict quarantine is the only practical defence.
- Gill flukes and external parasites: A risk when sourcing from high-turnover retail tanks. A quarantine period minimises transmission risk.
Health note: disease identification and medication dosing are outside the scope of a care profile. If a fish appears sick, compare symptoms against a reputable veterinary or fish-health reference before treating — misdiagnosis and overmedication cause more losses than many diseases.
How Long Do Buenos Aires Tetras Live?
With good care, Buenos Aires tetras live 3–5 years. The range reflects how much husbandry matters — a well-maintained, appropriately sized tank with steady temperatures and good feeding pushes toward the upper end; cramped, warm, overstocked conditions do the opposite. Most keepers see the full lifespan when baseline care is right from the start.
Frequently asked questions
Will Buenos Aires tetras eat my live plants?
Yes — they are notorious plant-nibblers and will shred soft-leaved species like cabomba, ambulia and hornwort quickly. Stick to tough, unpalatable plants (java fern, anubias, java moss) or go with a hardscape or artificial plant setup.
Are Buenos Aires tetras aggressive towards other fish?
They are mildly fin-nipping, especially in small groups. Keeping them in schools of six or more reduces fin-nipping directed at tank-mates, but avoid pairing them with long-finned or slow-moving fish such as angels or fancy guppies.
What you need to keep a buenos aires tetra
The baseline is a heated, filtered 80 L+ tank: a reliable heater to hold 18–26 °C (64–79 °F), a gentle filter that won't batter a buenos aires tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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