Freshwater fish, Characiformes (Characins), Information, Species, Tetras

Buenos Aires Tetra: Complete Species Overview

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by Jason Matthews



Buenos Aires tetra fish is a beginner-friendly freshwater species. They are quite popular because they have low maintenance needs and are a colorful addition to your aquarium. In addition, they are hardy like other tetra varieties; however, you still need to provide them with proper care requirements.

If you are considering getting Buenos Aries tetra varieties for your fish tank, here are the key things you need to know.


Scientific Name: Hyphessobrycon anisitsi

Common Names: Buenos Aries tetra, red cross fish, diamond spot, characin

Life Expectancy: 5 years

Adult size: About 2.75 – 3 inches


Beginner friendlyYes
Water temperature64-82F
Water pHA pH of 5.8-8.5
Water hardnessup to 35 dGH
Tank preferenceMid-level
Tank size20-30 gallons
BreedingEgg scatterer

Fun Fact

Although the Buenos Aries tetra fish was sold in huge numbers, this has significantly reduced because they tend to eat the live plants in the aquarium. This fish species can eat plants that other breeds can’t handle.


Like their name, the Buenos Aries tetra fish are originally from Argentina. They are found in the Rio de la Plata and other connecting rivers, streams, and lakes. 

Since they are freshwater species, they don’t survive well in polluted and salty waters. Buenos Aries tetras were discovered in 1907; therefore, they have been bred in captivity for more than six decades.


Buenos Aires Tetra fish species
Image credit: Neryx, Depositphotos

Generally, Buenos Aries tetras have the same shape as other tetras. However, their body color makes them stand out. They have a shimmering silver color with black patches and a narrow blue line that stretches from the gill to the tail fin. If you look at them in the right conditions, these fish species will shimmer in different colors.

These species have a distinct diamond-shaped black mark at the base of the tail fin. This extends to meet the blue midline. In addition, the pectoral, caudal, and anal fins have a red-orange color, while the dorsal fin is transparent. However, some variations might have a streak of red or black on the dorsal fin.

Gender Difference

You can tell the difference between males and females by looking at the color and size. Male Buenos Aries tetras are more colorful and brighter, and their fins have a stronger red color. On the other hand, the females are larger and have rounder bellies.

Average Size

Buenos Aries tetras are among the larger tetras. As adults, they can grow to about 2.75-3 inches. To help them achieve their maximum growth and size, it’s advisable to source them from respected sellers and stock them in optimal water conditions.


Generally, Buenos Aries tetras are peaceful varieties. They can be kept in a community tank, but they need to be in a group of at least six fish. However, they can be bullies if stocked together with vulnerable and smaller-sized fish; therefore, you should keep an eye out for that. They also nip at fins if you keep them with long-finned tankmates.

They may become stressed if stocked together with larger fish. When playing, they tend to dart around the aquarium in an odd manner, which should not be worrying. Additionally, you might see them eating plants in your tank if you have live plants. To avoid this, it’s better to have artificial plants.


Although Buenos Aries tetras are generally peaceful, you should not keep them with smaller varieties like neon tetras. They should also not be stocked together with long-finned varieties like angelfish and betta.

They do well with large tetras like serape and black widow. You can also keep them with gouramis, danios, barbs, Bolivian ram cichlid, German blue ram, and rainbowfish.

Tank Size and Conditions

An advantage of keeping Buenos Aries tetras is that they adapt quite well to life in captivity; therefore, they won’t be affected by environmental changes. However, you still need to provide the basic needs.

Your tank size depends on how many you plan to keep in the aquarium. They are schooling fish that require ample swimming space; therefore, a 20 gallon30 gallon fish tank would suffice. Stocking them in a cramped tank will increase their behavioral issues and make it hard to manage them.

The ideal water temperatures should be between 64-82F, while the pH levels should be between 5.5 to 8.5. Stick to these water parameters if you want your Buenos Aries tetras to stay healthy. You can maintain this quality by performing regular water tests.

Your aquarium should have decorations such as plants, rocks, and driftwood. However, this fish species has a reputation for destroying live plants. Therefore, you should avoid live plants and go for artificial options instead.


Bueno Aries tetras will eat pretty much everything since they are omnivores. In the wild, their diet comprises insects, plants, and crustaceans. Therefore, when you have them in captivity, you need to keep them as healthy as possible by providing a balanced diet.

Some of the foods you can feed them include dry flake or pellet food, leafy greens like spinach and lettuce, high-protein snacks, bloodworms, brine shrimp, and daphnia. You can feed them several times a day and provide only what they can finish within three minutes.


Buenos Aries tetras are among the easier fish species to breed. As egg scatterers, they lay about 2,000 eggs at a time. You can spawn them in groups or pairs. 

When choosing tetras to breed, go for the most colorful males. It’s best to have a separate breeding tank and to ensure that the water is slightly acidic.

After the eggs get laid in the breeding tank, remove the adults because they don’t exhibit any parental instincts. The eggs will hatch in about 24 hours, and the fry will start swimming in three to four days.


If you are looking for a beginner-friendly freshwater fish species to keep in your aquarium, the Buenos Aries tetras are an excellent choice. They are easy to care for as long as you maintain the basic conditions.

Featured image: JuanCarlosPalauDiaz, Pixabay


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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