Ruby Tetra (Axelrodia riesei)

Ruby Tetra (Axelrodia riesei)

Common Name: Ruby Tetra
Scientific Name: Axelrodia riesei
Size: 0.75–1 inch (adult)
Origin: Colombia – Río Meta and Río Vaupés tributaries
Temperament: Peaceful, shy, and schooling
Tank Size: 10+ gallons
Water Conditions:

• Temperature: 72–80°F (22–27°C)

• pH: 5.5–7.0

• Hardness: Soft to moderately soft (1–10 dGH)

The Ruby Tetra is a small, glowing jewel of a fish, prized for its rich red coloration that deepens in well-maintained, dimly lit aquariums. Native to the soft, tannin-rich waters of Colombia, this species does best in a planted tank with gentle filtration and subdued lighting.

Due to their small size and shy nature, Ruby Tetras should always be kept in groups of at least 6–8, where they will display more natural schooling behavior and bolder colors. They are an excellent addition to peaceful nano and community tanks.

Fun Facts:

• Males tend to be more vividly red than females, especially during breeding displays.

• In a blackwater tank setup with botanicals like Indian almond leaves or driftwood, their ruby hues truly shine.

• Their tiny size makes them ideal for nano aquariums, though they’re best kept with other calm, similarly-sized fish.

Diet:
Micro-predators—feed on micro pellets, crushed flakes, baby brine shrimp, daphnia, and other tiny live or frozen foods.

Compatibility:
Great with small, peaceful tankmates such as ember tetras, pygmy corydoras, and dwarf rasboras. Avoid aggressive or much larger species.

Bring a splash of natural elegance to your tank with the Ruby Tetra—a true hidden gem for aquarists who appreciate subtle beauty and serene schooling behavior.