Royal Blue Tetra Breeding Guide

Breeding the Royal Blue Tetra (Inpaichthys kerri): sexing by adipose-fin colour, a soft acidic spawning setup, egg scattering and rearing light-sensitive fry.

Overview

The Royal Blue Tetra (Inpaichthys kerri), also sold as the Purple or Royal Emperor Tetra, is a small Brazilian characid. It is an egg-scattering tetra that gives no parental care, so spawning is carried out in a dedicated tank from which the adults are removed once eggs are laid.

Sexing

Seriously Fish notes that females are far less colourful and stockier in body shape than males. A reliable cue is the adipose fin: males show a blue adipose fin while females have a predominantly red one.

Conditioning

For group spawning, condition about half a dozen of each sex on plenty of small live foods. For pair spawning, condition the sexes separately, then select the fattest female and best-coloured male.

Breeding Setup

• Spawning tank around 18 x 10 x 10 inches (about 45 x 25 x 25 cm).
• Very dim lighting.
• Temperature 24-28 C (75-82 F).
• pH 5.5-6.5 with general hardness around 1-5; soft, acidic water with RO water and peat filtration recommended.
• Clumps of fine-leaved plants such as java moss or spawning mops, or a mesh base that lets eggs fall out of reach.
• Gentle air-powered sponge filter.

Spawning Behavior & Trigger

For pair spawning, transfer the selected pair to the spawning tank in the evening; they should spawn the following morning. Eggs are scattered among the plants or fall through the mesh. Adults eat the eggs and must be removed immediately afterwards.

Egg & Fry Care

Eggs hatch in around 24-48 hours and the fry are free-swimming about 3-4 days later. Offer infusoria-type foods for the first several days, then microworm and brine shrimp nauplii as the fry grow.

Common Challenges

Egg predation by adults is the main hurdle, so timely removal is essential. As with related tetras, genuinely soft, acidic water and subdued lighting improve fertilisation and fry survival.