Buenos Aires Tetra
Hyphessobrycon anisitsi
Min Tank Size
80L
Adult Size
7.5 cm
Lifespan
5 years
School Size
6+
About
Native to the Parana River basin in South America, Buenos Aires Tetras have a reputation that precedes them. They're one of those fish that beginners discover by accident and experienced hobbyists deliberately choose for specific setups. The body is a clean silver with a bold red splash across the fins, particularly the tail and lower fins, making them genuinely striking in a group. They're chunky for a tetra, reaching around 7.5 cm as adults, which surprises people who picked them up as juveniles at the store.
Water parameters are almost laughably forgiving. They handle everything from slightly acidic to alkaline conditions and tolerate temperatures as low as 16C, which makes them viable for unheated setups in warmer climates. That cold tolerance is rare among tropical community fish and genuinely useful.
Feeding them is straightforward. They'll take flake, pellets, frozen or live foods without hesitation. The problem is they'll also take your plants. Soft-leaved plants like Amazon swords and Cryptocorynes are destroyed quickly. Even tougher plants like Java fern get nibbled over time. If you want greenery, stick to plastic or silk, or pair them with truly robust plants like Anubias on the off chance yours are less destructive than average.
They're not peaceful. Fin nipping is habitual, not occasional, and slow or long-finned fish will be harassed relentlessly. Keep them in groups of six or more to spread that energy around.
In the right tank, they're fast, bold, and genuinely entertaining to watch. Browse community tank builds featuring this species to see how people work around their quirks.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Buenos Aires Tetra together
Buenos Aires Tetra are shoaling fish and need company of their own kind. Keep a group of at least 6. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
Best paired with fast-moving, short-finned fish that can hold their own. Giant danios, tiger barbs, larger rainbowfish, and robust barbs like Odessa or Rosy Barbs work well. Avoid anything with long flowing fins, slow movement, or small enough to be mistaken for food. Bottom dwellers like larger Corydoras or Bristlenose Plecos generally coexist fine since they stay out of the tetra's zone. Shrimp will be picked off. In a 150-liter or larger tank, the aggression dilutes across more space and there's room for enough tankmates to create a balanced dynamic.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The biggest mistake is putting them in a planted tank expecting them to leave things alone. They won't. Even hobbyists who've read the warnings often test it anyway and regret it. The second mistake is understocking them, a pair or trio gets nippy and stressed. Six is the real minimum. They're otherwise easy, eating anything, tolerating wide parameter swings, and rarely getting sick. Just make sure the tank has a lid since they're capable jumpers when startled.
Behavior & Aggression
Buenos Aires Tetras nip fins consistently, not just under stress. Long-finned fish like bettas, fancy guppies, and angelfish are especially at risk. The behavior doesn't really stop with larger groups, but bigger schools do reduce any one fish bearing the brunt of it. They can also be pushy at feeding time and may outcompete slower tankmates. Keeping them well-fed and in active, similarly-sized company helps, but won't eliminate nipping entirely.
Things to Know
- Remove one of the two duplicate plant-destruction notes. Notes 1 and 5 convey the same information.
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