The Flame Tetra, also widely known as the Von Rio Tetra, is a small but exceptionally vibrant addition to the community aquarium. Hailing originally from the coastal rivers of Rio de Janeiro, Brazil, these fish are a masterclass in colour gradients—transitioning from a cool silver at the snout to a fiery, smouldering red at the tail.

While they are critically endangered in their natural habitat due to urbanisation, they are fortunately one of the most successfully captive-bred species in the hobby, ensuring their “fiery” presence remains available to aquarists worldwide.

At a Glance

Physical Description

The Flame Tetra is easily identified by its distinctive “dipped in ink” appearance.

• The Body: The front half of the fish is a shimmering metallic silver or bronze, which gives way to a deep, translucent orange-red towards the posterior.

• The Bars: Two bold, dark vertical bars sit just behind the gill covers (the operculum).

• The Fins: The dorsal and anal fins are typically edged in a deep red, with the anal fin of the male often possessing a sharp black border, whereas the female’s fin is usually lighter.

Aquarium Requirements

The Setup

Flame Tetras are not particularly demanding, but to see their best colours, you should aim to replicate a lush, shaded environment.

• Substrate: Use a dark substrate. Against a light or sandy bottom, Flame Tetras tend to “wash out” and look pale. A dark soil or gravel makes their red pigment pop.

• Decoration: They appreciate a well-planted tank with plenty of mid-ground cover. Floating plants are a great addition, as dimmed lighting encourages them to feel secure and display more intense colouration.

• Tank Size: A minimum of 60 litres is recommended for a proper shoal.

Water Parameters

These fish are hardy and adaptable, making them a fantastic choice for beginners.

• Temperature: 22°C – 28°C (72°F – 82°F).

• pH: 5.5 – 7.5 (They prefer slightly acidic to neutral).

• Hardness: Soft to medium (up to 15 dGH).

Diet and Nutrition

The Flame Tetra is an unfussy omnivore. In the wild, they hunt small insects and crustaceans, but in the home aquarium, they will accept almost anything that fits in their mouths.

• Daily Feeding: A high-quality crushed flake or micro-pellet.

• Conditioning: To bring out that deep red “flame,” supplement their diet with live or frozen Daphnia, Cyclops, or Baby Brine Shrimp.

• Variety: Rotating their food every few days ensures they receive the carotenoids needed to maintain their pigment.

Social Behaviour and Compatibility

The Flame Tetra is a shoaling fish. Keeping them in isolation is stressful and will significantly shorten their lifespan.

• Group Size: A minimum of 6 to 8 individuals is essential, though a group of 12 or more creates a stunning “ember” effect as they move through the plants.

• Compatibility: They are the “perfect neighbours.” They get along famously with:

  • Other small Tetras and Rasboras.

  • Corydoras catfish (like the Hoplisoma mentioned earlier).

  • Dwarf Cichlids (Apistogramma).

  • Peaceful Gouramis.

• Avoid: Large, predatory fish that might mistake them for a snack, or overly boisterous species that might out-compete them for food.

Pro Tip for Aquarists: > If your Flame Tetras look a bit “dull” when you first bring them home from the shop, don’t panic! This species is notoriously sensitive to transport stress. Once they settle into a planted tank with stable water and a good meal, their “flames” will ignite within a few days.