Characteristics, Origin, diseases, cost and Helpful Information for the Hobbyist
The Buenos Aires tetra is extremely popular due to its hardiness and ease of care. These fish were once sold in large numbers, but due to their propensity for eating aquarium plants, they have become less popular over the years. Specimens are mostly captive-bred from commercial fish farms in Florida.
COMMON NAMES: Buenos Aires tetra, diamond spot characin, red cross fish
SCIENTIFIC NAME: Hyphessobrycon anisitsi
ADULT SIZE: 2.75 inches (7 centimeters)
LIFE EXPECTANCY: 5 years
|Origin||Argentina, southeastern Brazil, Paraguay|
|Social||Peaceful, shoaling fish|
|Minimum Tank Size||30 gallon|
|pH||5.8 to 8.5|
|Hardness||Up to 35 dGH|
|Temperature||64 to 82 F (18 to 28 C)|
Origin and Distribution
The Buenos Aires tetra derives its name from the capital city of Argentina. The city sits on the western shore of the Río de la Plata, located along the southeastern coastline of South America. Considered a river by some and a gulf by others, the Río de la Plata is formed by the joining of the Paraná and Uruguay Rivers, both of which are home to the Buenos Aires tetra. In the wild, they are additionally found in rivers, ponds, lakes, and streams. They are freshwater fish and do not do well in highly salty or polluted waters.
Colors and Markings
The Buenos Aires tetra is one of the larger tetras as it can grow to nearly three inches in size. Its body is silvery with a narrow blue line that starts behind the gill and ends at the caudal (tail) fin, where there is a black diamond-shaped spot. The fins are orange-red and a splash of red can be seen at the top of the eye. Several color variations have been bred including one that has a yellow tail; there is also an albino variety.
Buenos Aires tetras are social fish that swim in schools. Although this species of tetra is generally peaceful, avoid keeping Buenos Aires tetras with smaller fish such as the neon tetra. Also, avoid housing them with long-finned fish such as the betta and angelfish. Buenos Aires tetras will nip at the fins of long-finned tankmates.
The Buenos Aires tetra does well with larger sized tetras, such as the black widow or serpae tetra, as well as with barbs, danios, gouramis, and rainbowfish. Bottom-dwelling fish are also good companions. A school of Buenos Aires tetras are also good dither fish among non-aggressive cichlids; they help relax cichlids enough to come out of hiding.
Buenos Aires Tetra Habitat and Care
The undemanding Buenos Aires tetra is adaptable to a range of aquarium conditions. Acceptable water temperatures can span all the way from the mid-60s to 80 degrees Fahrenheit, making it suitable for heated as well as unheated tanks. It is a highly active fish, and it does require a sizable open swimming space. Longer tanks are ideal.
The Buenos Aires tetra is not suitable for most live planted tanks, however, as it is known to devour vegetation. Use artificial plants instead, or select sturdy live plants such as anubias, Java fern, or vallisneria. Round out the décor with driftwood and rocks around the periphery of the tank, and your Buenos Aires tetras will be quite at home.
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.
The Buenos Aires tetra is extra sensitive to the nitrates and phosphates that build up over time, and water hardness increases due to evaporation. To combat these ever-changing conditions, water should be replaced on a regular basis. At least 25 to 50 percent of the tank water should be replaced every other week especially if the tank is densely stocked.
Buenos Aires Tetra Diet and Feeding
Buenos Aires tetras are omnivores that will accept a wide variety of foods. Feed these tetras several times a day but feed only what they can consume in three minutes or less at each feeding.
In the wild, they primarily feed on worms, crustaceans, insects, and plants, but in the aquarium, they will generally eat all kinds of live, fresh, and flake foods. Given its propensity for eating live plants, provide this fish with some lettuce, spinach, or other vegetation to munch on. In lieu of fresh vegetation, you can provide a good quality spirulina flake food.
Flake, dried, and freeze-dried foods add well-needed variety to their diet and will be readily accepted. To keep these tetras at their best and most colorful, offer live foods such as bloodworms, daphnia, brine shrimp, and mosquito larvae. Feeding Your Fish Live Food
Males of the species have brighter, redder fins and are generally more colorful overall, particularly during spawning. Females are larger and broader with a rounder belly.
Breeding the Buenos Aires Tetra
Buenos Aires tetras are easy to breed; they are egg scattering fish that can be spawned in pairs or in groups. If spawned in a group, use approximately the same number of males as females. A mature female’s belly will become nicely rounded when she is full of eggs. Choose males that are the most colorful.
Condition all spawning fish with live foods prior to spawning attempts. Keep the water slightly acidic to neutral with a pH of 6.5 to 7.2; keep the water temperature at 75 degrees Fahrenheit. Gentle filtration, such a sponge filter is recommended. Provide sturdy plants such as Java moss or spawning mops on which the fish will scatter their adhesive eggs.
This species will usually begin to spawn at dawn. Females may lay as many as 2,000 eggs, depositing them on the plants or green floss. Remove the adults once the eggs have been laid. After spawning, these fish exhibit no parental care and will eat the eggs and young, so make this your separate rearing tank.
The eggs will hatch in approximately 24 hours. In three to four days the fry will have consumed their egg sacs and will be free swimming. Initially, feed the fry infusoria or commercially prepared fry food such as Liquifry. As they grow larger, feed them freshly hatched brine shrimp, micro worms, or finely ground high-quality flake food or fry food.
Care Level Easy Temperament Peaceful Color Form Red, Silver Diet Omnivore Water Conditions 64-82° F, KH 12-30, pH 7.0-8.3 Max. Size 2½” Origin China Family Characidae Minimum Tank Size 10 gallons Compatibility View Chart
What do these Quick Stats mean?
The Buenos Aires Tetra is a South American fish that will make a great addition to any community aquarium. It has a slender silver body with red fins.
The Buenos Aires Tetra can be housed in an aquarium with other soft water fish. Tetras are a schooling fish that work well in groups of six or more fish of the same species. Artificial plants, rocks and driftwood help to enhance its natural habitat and provide hiding spaces. The Buenos Aires Tetra will eat most live plants, except Java Fern.
Buenos Aires Tetras breed occasionally in an aquarium setting and a hospital or “breeding tank” will be necessary. Slightly acidic water is best for optimal breeding habits. After the eggs begin to hatch, removing the parents will reduce the number of lost fry.
The Buenos Aires Tetra will accept many small foods such as brine shrimp or daphnia, freeze-dried bloodworms and tubifex, and a high quality flake food.
Approximate Purchase Size: 1/2″ to 1-1/4″
Buenos Aires Tetra – Quick Aquarium Care
- Aquarist Experience Level: Beginner
- 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)
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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.
These schooling fish inhabit a range of biotypes, including 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 fish that can reach up to 2.75 inches (7 cm) and have a lifespan of 5 to 6 years. Its silvery color 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. Its most distinguishing characteristic is the caudal peduncle, which features 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 to 6 years.
Fish Keeping Difficulty
The Buenos Aires Tetra is a hardy fish that is good for the beginning fish keeper. They are very durable and long-lived, and do not have any special needs or requirements that have to be met for them to thrive. However, they are hearty feeders that must be kept well-fed or they may resort to nipping at their long-finned companions. Keeping them in a school will help reduce fin-nipping. They will also eat live aquarium plants.
- Aquarium Hardiness: Moderately hardy
- Aquarist Experience Level: Beginner
Foods and Feeding
The Buenos Aires Tetras are omnivorous. In the wild they primarily feed on worms, crustaceans, insects, and plants, but in the aquarium they will generally eat all kinds of live, fresh, and flake foods. To keep a good balance, give them a high quality flake food every day. 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
- Flake Food: Yes
- Tablet / Pellet: Yes
- Live foods (fishes, shrimps, worms): Some of Diet
- Vegetable Food: Some of Diet – This fish loves to eat aquarium plants.
- Meaty Food: Some of Diet
- Feeding Frequency: Several feedings per day
Buenos Aires Tetras are not exceptionally difficult to care for, provided their water is kept clean. Aquariums are closed systems and regardless of size, all need some maintenance. With home aquariums, the nitrates and phosphates build up over time, and water hardness increases due to evaporation. To combat these ever-changing conditions, water should be replaced on a regular basis. At least 25 to 50% of the tank water should be replaced every other week, especially if the tank is densely stocked.
- Water Changes: Bi-weekly
This fish is a very active swimmer and needs plenty of open space. It also likes to be kept in a school with 5 or more companions of its own kind. 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. Thus, 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 – These fish will spawn at 75° F (24° C).
- 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.
The Buenos Aires Tetra are generally a good community fish. They are quite active and will school when provided with plenty of space. These tetras are best kept with their own kind in a school of 5 or more or with 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. Sometimes, they can be outright aggressive, so monitor them in community tanks. To avoid fin nipping, keeping this fish in schools of 5 or more will restrict most of the aggression to within the school.
Good tankmates are similiarly 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 will nip and harrass this tetra, so they do not make good tankmates.
- 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 Buenos Aires Tetras can be outright aggressive, especially if not kept in a school.
- Semi-Aggressive (): Threat
- Aggressive (): Threat
- Large Semi-Aggressive (): Threat
- Large Aggressive, Predatory (): Threat
- Slow Swimmers & Eaters (): Monitor – Tetras can out compete them for food.
- 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 males have brighter, red fins, sometimes tending towards yellow. The female is fuller-bodied with a more rounded stomach.
Breeding / Reproduction
Buenos Aires Tetras have been bred in captivity. These egg scattering spawners exhibit no parental care, but they are easy to breed, which makes them ideal candidates for the beginning aquarist interested in a breeding project. Adults in good condition will spawn in a mature community tank, but the eggs and fry will most often be eaten. To get the best mortality rate for the fry, the aquarist must use a separate breeding tank.
The breeding tank should be well-planted and around 10 or 20 gallons. Keep the tank dimly lit with clumps of spawning mops or java moss, so the female has a place to deposit the eggs. A layer of mesh also works if it is wide enough for eggs to pass through but small enough to keep parents out. The water should be soft and slightly acidic to neutral with a pH of 6.5 to 7.2 and a temperature of 75° F (24° C). A small, air-powered sponge filter is needed for gentle filtration and water movement.
These fish can be bred as a pair or in a small group consisting of either an equal number of males and females or 1 to 2 males with several females. Prior to spawning, condition the breeders with a good supply of small, live foods. After a few days, select a breeding pair or small group and transfer them into the breeding tank in the evening. A mature female’s belly will become nicely rounded when she is full of eggs. Choose males that are the most colorful.
They will usually begin to spawn at dawn. Females may lay as many as 2000 egg during this time, depositing them on the plants or green floss. The parents should be removed immediately after spawning, or they will eat the eggs. The eggs will begin to hatch in 24 to 36 hours, and the fry will be free-swimming in another 3 to 4 days. For the first few days, feed the fry infusoria-type foods until they can feed on microworm or brine shrimp nauplii. See Breeding Freshwater Fish: Characins for a general description of breeding processes, and see Fish Food for Fry for information about types of foods for raising the young.
- Ease of Breeding: Easy
As with most fish, 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 that anything you add to your tank can introduce disease. 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 as 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 dealt with 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 a well-balanced diet.
The more closely their environment resembles their natural habitat, the less stress the fish will have, making them healthier and happier. It is recommended to read up on the common tank diseases. Knowing the signs of common tank diseases and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Buenos Aires Tetra is reasonably priced and readily available both in fish stores and online.
- Animal-World References: Freshwater Fish and Plants
- Dr. Rüdiger Riehl and Hans A. Baensch, Aquarium Atlas Vol. 1, Publisher Hans A. Baensch, 1991
- Joseph S. Nelson, Fishes of the World, Wiley, 2006.
- Greg Jennings (Editor), 500 Freshwater Aquarium Fish, Firefly Books Ltd, 2006.
- David Goodwin, The Practical Aquarium Fish Handbook , Sterling Publishing Company, 2003
- Dr. Herbert R. Axelrod, Aquarium Fishes of the World, TFH Publications, 1998
- Hyphessobrycon anisitsi (Eigenmann, 1907) Buenos Aires tetra, Fishbase.org