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Contents
Overview
The Buenos Aires tetra is a silvery characin with a bluish sheen, red fins and a black diamond-shaped spot at the base of the tail. It comes from the Paraná and Río de la Plata basins in Argentina, Paraguay and southern Brazil, so it tolerates cooler water than most tetras.
It is one of the toughest tetras around and was a staple of home aquariums in the 1960s and 70s. It is not a fit for every community tank, though: it is large, jittery and greedy, it nips fins and it eats many soft-leaved plants. It is a great choice for roomy, busy tanks with sturdy fish, not for a calm planted tank with delicate species.
Care and tank setup
This is a tireless swimmer that needs a long tank: about 40 gallons (150 L) and at least 40 inches (100 cm) of length for a school of eight. Use a cycled tank, strong filtration (they are messy) and a lid, since they jump.
- Plants: they shred soft plants such as elodea, cabomba and limnophila. Go with tough species like anubias, java fern and cryptocorynes, or artificial plants.
- Water: they accept almost any reasonable tap water. They handle cooler rooms, but a heater keeps conditions stable.
- Tank mates: robust barbs, giant danios, corydoras, plecos, larger tetras and mid-sized South American cichlids. Never with angelfish, bettas, fancy guppies or shrimp.
A big school keeps aggression focused within the group; in groups of three or four, harassment of tank mates is usually much worse.
Feeding
A very greedy omnivore with a strong appetite for greens. Flakes, pellets and frozen foods vanish instantly, but include spirulina-based food or blanched vegetables (spinach, peas, zucchini) several times a week: it supports their health and helps spare your plants a little. Split the daily ration into two feedings so slower tank mates get their share.
Breeding
An easy egg scatterer to breed. A well-conditioned pair placed in a breeding tank with fine-leaved plants or spawning mops and mesh on the bottom usually spawns within a day or two, leaving hundreds of eggs. The adults eat them, so remove the parents right away. Fry hatch in about a day and take infusoria, then baby brine shrimp.
Compatible tank mates
Species from our database that share water parameters, size and temperament with the Buenos Aires tetra. Calculated from the data in each profile.
Bristlenose pleco Ancistrus sp. 26 gal (100 L) · 72–81 °F (22–27 °C) 
Bronze cory Corydoras aeneus 21 gal (80 L) · 72–81 °F (22–27 °C) 
Zebra danio Danio rerio 16 gal (60 L) · 64–77 °F (18–25 °C) 
Cherry barb Puntius titteya 16 gal (60 L) · 73–81 °F (23–27 °C) 
Tiger barb Puntigrus tetrazona 26 gal (100 L) · 72–79 °F (22–26 °C) 
Nerite snail Neritina natalensis 5 gal (20 L) · 72–82 °F (22–28 °C) 
Horned nerite snail Clithon corona 5 gal (20 L) · 72–82 °F (22–28 °C) 
Common goldfish Carassius auratus 79 gal (300 L) · 50–75 °F (10–24 °C) 
Panda cory Corydoras panda 16 gal (60 L) · 68–77 °F (20–25 °C) 
Dwarf gourami Trichogaster lalius 16 gal (60 L) · 75–82 °F (24–28 °C) 
Molly Poecilia sphenops 26 gal (100 L) · 75–82 °F (24–28 °C) 
Otocinclus catfish Otocinclus vestitus 16 gal (60 L) · 70–79 °F (21–26 °C) Check the compatibility of your whole tank →
What not to keep it with
Popular species you shouldn’t house with the Buenos Aires tetra, and why.
- Betta fish: nips long fins
- Discus: incompatible temperatures
- Angelfish: nips long fins
- Guppy: nips long fins
- Oranda goldfish: nips long fins
- Oscar: one may eat the other due to size, incompatible temperaments
- Ember tetra: one may eat the other due to size
- Amano shrimp: eats shrimp
Recommended equipment
What you need to keep the Buenos Aires tetra healthy, checked against Amazon stock.
Frequently asked questions
How many liters does a Buenos Aires tetra need?
At least about 150 liters for a group of at least 8 fish. More space always helps keep the water stable.
What water temperature does the Buenos Aires tetra need?
Between 18 and 26 °C, with a pH of 6 to 8.
What fish can live with the Buenos Aires tetra?
Based on water, size and temperament, it fits with species such as Bristlenose pleco, Bronze cory, Zebra danio, Cherry barb and Tiger barb. Use our compatibility calculator to check your whole tank.
Can the Buenos Aires tetra be kept with shrimp?
Not recommended: because of its size or instinct, it will eat shrimp.
