Elevate your aquarium’s color palette with the Royal Tetra, a sophisticated and vibrant species that brings a unique shade of violet to the freshwater hobby. Often called the Purple Emperor Tetra, the Inpaichthys kerri is celebrated for its shimmering lavender-to-deep-blue body and its striking dark lateral stripe. This hardy schooling fish is a peaceful yet active addition, perfect for hobbyists looking for an elegant alternative to more common tetra species.

Quick Stats

• Scientific Name: Inpaichthys kerri

• Common Names: Royal Tetra, Blue Emperor Tetra, Purple Emperor Tetra

• Care Level: Easy

• Temperament: Peaceful and social

• Lifespan: 3 to 5 years

• Max Size: 1.5 to 2 inches

Place of Origin

The Royal Tetra is native to the Aripuanã River basin in Brazil, a tributary of the mighty Amazon. They typically inhabit slow-moving forest streams and tributaries where the water is stained tea-colored by fallen leaves and tannins (blackwater habitats).

Ideal Environment & Tank Size

To see these fish at their most confident, a minimum tank size of 20 gallons is recommended. Being a schooling species, they should be kept in groups of at least 6 to 10 to encourage their natural social structure and best coloration.

• Substrate & Decor: They look most stunning against a dark substrate. Incorporate driftwood, dried leaf litter (like Catappa leaves), and dense planting.

• Lighting: They prefer slightly dimmed or dappled lighting. Using floating plants like Salvinia or Amazon Frogbit can help mimic their natural shaded environment.

• Water Parameters:

  • Temperature: 74°F to 82°F

  • pH: 5.5 – 7.5 (They thrive in slightly acidic to neutral water)

  • Hardness: 1–12 dGH

Feeding & Diet

Royal Tetras are omnivores and are exceptionally easy to feed in the home aquarium.

• Primary Diet: High-quality micro-pellets or flake foods.

• Conditioning: To maintain their deep purple and blue hues, provide a varied diet including frozen or live bloodworms, brine shrimp, and daphnia.

Compatible Tank Mates

These are very peaceful aquarium fish that coexist well with a wide variety of neighbors.

• Best Mates: Other small tetras, rasboras, Corydoras catfish, dwarf cichlids (like Apistogramma), and peaceful gouramis. They are also generally safe with freshwater shrimp and snails.

• Avoid: Large, aggressive, or predatory fish that might see the Royal Tetra as a food source.

Breeding the Royal Tetra

Breeding Inpaichthys kerri is achievable for the intermediate hobbyist.

1. Preparation: Condition a pair or a small group with high-protein live foods in a separate breeding tank.

2. The Trigger: Use soft, slightly acidic water and provide fine-leafed plants like Java Moss for egg-scattering.

3. Spawning: They are egg-scatterers and do not provide parental care. Once eggs are laid among the plants, remove the adults to prevent them from eating the spawn.

4. Fry Care: Eggs hatch in about 24–36 hours. The fry are very small and will require infusoria or liquid fry food initially before graduating to baby brine shrimp.