Buenos Aires Tetra

Family: Characidae Buenos Aires Tetra, Hyphessobrycon anisitsiHyphessobrycon anisitsiPhoto © Animal-World: Courtesy David Brough
Latest Reader Comment - See More
I have three of these guys in my 29 gallon blackwater aquarium. To add more color, I purchased a shoal of 9 neon tetras. Within an hour of their introduction, my... (more)  Jake

One of the most easily kept fish, the Buenos Aires Tetra is great for the beginning aquarist!

The Buenos Aires Tetras Hyphessobrycon anisitsi are very hardy, long lived, and prolific breeders. They are handsome full-bodied fish that can reach up to about 2 3/4 inches (7 cm) in length with a life span of about 5 - 6 years.

They have a pretty silvery color overall, picking up flashy neon highlights. But they are immediately distinguished by the bold black 'cross' shaped pattern at the base of the tail fin accented with red above and below.

These fish are great for beginners. They can adapt to most water conditions within reason and have no special requirements or considerations. Being fairly peaceful fish they will do very well in a community tank, but they do have a big appetite. They must be kept well fed because if they get hungry they will nip the fins on any of their long-finned tankmates!  They are best if kept in large groups of five or more individuals. Being kept in a good sized school will also cut down on their desire to nip at the other fish.

For many years they were one of the most popular fish in the aquarium hobby. The Buenos Aires Tetra however, will eat live plants. With so many people today growing plants in their aquariums, they have fallen a bit out of favor. If you are keeping an aquarium with artificial plants they make a wonderful addition to a community tank.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

Geographic Distribution
Hyphessobrycon anisitsi
Data provided by FishBase.org
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Characidae
  • Genus: Hyphessobrycon
  • Species: anisitsi
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Buenos Aires Tetra - Quick Aquarium Care
  • Size of fish - inches: 2.8 inches (6.99 cm)
  • Minimum Tank Size: 25 gal (95 L)
  • Temperament: Semi-aggressive
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 64.0 to 82.0° F (17.8 to 27.8° C)
  • Aquarist Experience Level: Beginner
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Habitat: Distribution / Background

The Buenos Aires Tetra Hyphessobrycon anisitsi (previously Hemigrammus caudovittatus and Hemigrammus anisitsi) was described by Eigenmann in 1907. The species is not listed on the IUCN Red List. They are found in South America in the La Plata region, Argentina, Paraguay and southeastern Brazil.

They are a schooling fish that inhabits a range of biotypes which include streams, rivers, lakes and ponds.  In nature these tetras feed on worms, crustaceans, insects and plants.

  • Scientific Name: Hyphessobrycon anisitsi
  • Social Grouping: Groups - .
  • IUCN Red List: NE - Not Evaluated or not listed


The Buenos Aires Tetra is a full-bodied large tetra species that can reach up to 2.75 inches (7 cm) with a lifespan of 5 - 6 years. It has a silvery color that picks up flashy neon highlights. The top and bottom of the tail fin is generally red, as are the pelvic and anal fins. The dorsal fin also has a hint of red. Their most distinguishing characteristic is the caudal peduncle which has a bold black 'cross' shape.

  • Size of fish - inches: 2.8 inches (6.99 cm)
  • Lifespan: 6 years - They have a lifespan of about 5 - 6 years.

Fish Keeping Difficulty

The Buenos Aires Tetra is a hardy fish that is good for the beginner fish keeper.  They do not have any special needs or requirements that have to be met for them to thrive.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

Since they are omnivorous the Buenos Aires Tetra will generally eat all kinds of live. fresh, and flake foods. To keep a good balance give them a high quality flake food everyday. To keep these tetras at their best and most colorful, offer regular meals of live and frozen foods such as bloodworms, daphnia and brine shrimp.  Vegetables should also be added to their diet.  Blanched spinach is a great choice.  Feed these tetras several times a day and only what they can consume in 3 minutes or less at each feeding.

  • Diet Type: Omnivore - This fish loves to eat aquarium plants.
  • Flake Food: Yes
  • Tablet Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Buenos Aires Tetras are not exceptionally difficult to care for provided their water is kept clean. Aquariums are closed systems and regardless on size all need some maintenance. With home aquariums the nitrate and phosphates build up over time and the water hardness increases due to evaporation. To combat these ever changing conditions water should be replaced on a regular basis. At least 25 - 50% of the tank water should be replaced every other week, especially if the tank is densely stocked.

  • Water Changes: Bi-weekly

Aquarium Setup

This fish is a very active swimmer so needs plenty of open space. It also likes to be kept with companions of its own kind in a group of 5 or more so it can school. Keep Buenos Aires Tetras in a tank at least 20 inches long and ideally 25 or more gallons to provide them with plenty of space for swimming and shoaling. They are happy with any type of substrate and do fine with normal aquarium lighting. However, the tank should be securely covered as these fish are skilled jumpers and will probably do so if given the opportunity.

This is a very undemanding species, as can be seen by the wide range of acceptable conditions. However they will eat most plants with the possible exception of Java Fern. So the tank should mostly be decorated with driftwood, rocks, and plastic plants.

  • Minimum Tank Size: 25 gal (95 L) - This fish is very active and requires space and companions of its own kind so it can school.
  • Suitable for Nano Tank: Yes
  • Substrate Type: Any
  • Lighting Needs: Moderate - normal lighting
  • Temperature: 64.0 to 82.0° F (17.8 to 27.8° C)
  • Breeding Temperature: 75.0° F
  • Range ph: 6.0-8.0
  • Hardness Range: 2 - 30 dGH
  • Brackish: No
  • Water Movement: Strong
  • Water Region: All - These fish will swim in all areas of the aquarium.

Social Behaviors

The Buenos Aires Tetra are generally a good community fish. They are quite active and when provided with plenty of space, they will school. These tetras are best kept with their own kind in a school of 5 or more, or other fish that can tolerate their boisterous behavior. Just remember to keep them well fed so they don't snack on the fins of their tankmates!

Good tankmates are similiar sized tetras, rainbowfish, larger rasboras, barbs and danionins.  Non-aggressive cichlids also do well with these tetras.  Slow moving long finned fish like gouramis, anabantoids and dwarf cichlids do not do well with these tetras and will nip and harrass this tetra.  To avoid fin nipping, keep this fish in schools of 5 or more and most of the aggression will be kept within the school.

  • Venomous: No
  • Temperament: Semi-aggressive - Although not usually aggressive, this fish is very active and will irritate more temperate fish. It is also a notorious fin nipper so select tankmates carefully.
  • Compatible with:
    • Same species - conspecifics: Yes - Best kept in a school of 5 or more.
    • Peaceful fish (): Monitor - Watch for fin nipping induced stress in other fish. Sometimes they can be outright aggressive so monitor them in community tanks.
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Slow Swimmers & Eaters (): Monitor
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Threat - One of the only drawbacks to this fish is that it will eat plants.

Sex: Sexual differences

The male will have brighter red fins, sometimes tending towards yellow. The female is fuller bodied and has a more rounded stomach.

Breeding / Reproduction

The Buenos Aires Tetra are egglayers. The female will lay eggs on plants or green floss. This tetra is fairly easy to breed. To get the best mortality rate for your fry, it is recommended to set up a second tank. An air powered sponge filter will work best. Fine leaved plants and spawning mops should be used to give the fish a place to deposit their eggs. A mesh can also be used as long as the holes are large enough for the eggs to pass through and able to keep the parents put. Tank should be kept at 75 degrees and water should be slightly soft and acidic.

These tetras should be kept in groups of 6 males and 6 females for best results. Feed these tetras a good supply of small live food and they will normally start to spawn. Eggs will begin to hatch in 24-36 hours and the fry able to free swim with in 4 days. For a description of breeding characin fish, see Breeding Freshwater Fish: Characins.

  • Ease of Breeding: Easy

Fish Diseases

As with most fish the Buenos Aires Tetra are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. Buenos Aires Tetra are extremely hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won't have to deal with health problems or disease. Remember anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.

A good thing about Buenos Aires Tetra is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Buenos Aires Tetra the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. Stressed fish are more likely to acquire disease.

For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments. This is a great source for information on disease and treatments. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. Buenos Aires Tetra are very resilient


The Buenos Aires Tetra is readily available, both in fish stores and on line, and is reasonably priced.


Author: David Brough CFS, Jeremy Roche
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Lastest Animal Stories on Buenos Aires Tetra

Jake - 2014-06-16
I have three of these guys in my 29 gallon blackwater aquarium. To add more color, I purchased a shoal of 9 neon tetras. Within an hour of their introduction, my shoal was down to two neons. The two survivors look stressed and I want to get them into a school again. Any suggestions on how I can stop them from eating neons?

  • Clarice Brough - 2014-06-27
    It sounds like, from their point of view, that 'neons are on the menu!' I don't think you will be able to keep these fish together in your current tank, perhaps if you get a bigger tank with lots of plants and hiding places, you may keep them together successfully, but these guys they now see them as lunch.
  • Heath Hunter - 2014-09-04
    Remove the b.a. and rearrange the tank. Leave the school of neon to get along with the new setup till they seem calm/comfy. Add the b.a. and turn the lights off for a day. They should get along without the territory battle to drive them. It may even help having no decorations at first.
Tom Pietruszka - 2009-11-01

The Buenos Aires Tetras are great fish; they are excellent in my 300 gallon community aquarium, even leaving the tiny Glowlight tetras alone. Having more than 6 of them helps minimize any aggression toward other fish. A while back, I purchased a few more smaller Buenos Aires Tetras, and had them for a time in a 10 gallon quarantine tank. Very recently, I purchased a few more Glowlight tetras and Bloodfin tetras and put them in the quarantine tank that the Buenos Aires Tetras had been in. To my surprise, I noticed babies swimming around in the quarantine tank, so I removed the Glowlights and Bloodfins and placed them temporarily in a tank with some catfish. Apparently, the Buenos Aires Tetras that I had in quarantine had laid eggs! And our well water is fairly hard! These are really easy fish to breed apparently!

crystal - 2004-08-23
My Bruno Aries Tetra has such a personality! He is ina community tank with black neons and neon tetras, and schools well with them, and not agressive towards them at all. When I come up to the tank, he always swims over to whatever side I am on as if to say hi.

Deedee - 2005-03-03
Got 5 of these guys in a smallish tank just for them, with a mopane bog wood root with a huge java fern stuck to it with a couple other plants up and a sump down full of more plants. The tank has a MILWAUKEE SMS122 pH/CO2 Controller so plants are always lush and the cylinders last forever because of the controllers... but back to these lovely fish... I looked in the tank one day last week and there, sitting pretty as can be is a 6th! A new baby the size of a small neon! I had no idea it had even been there obviously the dense java fern servered it well. Baby and 5 parents all doing great together.

floridafishkeeper - 2014-06-15
I have three of these fish in my 29 gallon amazon blackwater aquarium, along with one panda corydoras. To bring more activity to the tank, I bought a shoal of nine neon tetras. Within an hour of bringing them home, the trio had eaten seven out of nine of the neon tetras. Is this normal?

  • Clarice Brough - 2014-06-27
    Hey Jake, I answered this below... but here's a re-cap: 'It sounds like, from their point of view, that 'neons are on the menu!' I don't think you will be able to keep these fish together in your current tank, perhaps if you get a bigger tank with lots of plants and hiding places, you may keep them together successfully, but these guys they now see them as lunch.'

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