Glowlight Rasbora Breeding Guide
How to breed Trigonostigma hengeli: conditioning, very soft acidic water, eggs deposited on the underside of broad leaves, and 24-48 hour hatch.
Overview
Trigonostigma hengeli is a small rasbora that uses an unusual reproductive strategy: rather than scattering eggs randomly, it attaches them to the underside of broad plant leaves. It exhibits no parental care and is often described as difficult to breed, possibly because fish a year or older spawn more successfully than younger individuals.
Sexing
Mature females are usually deeper-bodied and slightly larger, while males are slimmer and more intensely coloured.
Conditioning
Feed small live and frozen foods two to three times daily for several weeks before attempting to spawn. Readiness shows when the females are full of eggs and the males display intense colour while competing for attention.
Breeding Setup
- Dimly lit tank with a bare or mesh base that lets failed eggs pass out of reach of the adults, or plastic grass matting
- Broad-leaved plants such as Microsorum or Cryptocoryne (or artificial equivalents) for egg attachment
- pH 5.0-6.0 and hardness 1-5 dGH
- Temperature at the upper end of the range, about 27-28°C
- An optional small air-powered sponge filter
Spawning Behavior & Trigger
Pairs often position themselves inverted to deposit eggs on the underside of broad leaves, and several dry runs may occur before egg-laying actually begins.
Egg & Fry Care
Because there is no parental care, remove the adults or the eggs immediately after spawning to prevent predation. Incubation is 24-48 hours depending on temperature, and the fry become free-swimming after about a week. Start the fry on Paramecium, then move to Artemia nauplii and microworm once they are large enough.
Common Challenges
Achieving the very soft, acidic water this species needs is the main obstacle, and using mature, year-old breeders improves the chances of a successful spawn.