Green Discus Breeding Guide
How to breed Symphysodon discus: pairing, soft acidic water, substrate spawning, and the fry feeding on parental skin secretion.
Overview
Green discus (Symphysodon tarzoo, also treated within the S. aequifasciatus complex) is a substrate-spawning cichlid of the upper Amazon. It is regarded as an advanced subject: spawning depends on a compatible pair, very soft acidic water and stable conditions. As with most cichlids, brood care is highly developed, and both parents tend the eggs and fry together.
Sexing
Discus are difficult to sex. Once fish exceed roughly 10 cm, females tend to retain rounder dorsal fins while males develop more pointed ones; males often appear larger with thicker lips. The only definitive confirmation comes from observing the breeding tube during spawning. Sexual maturity is reached at around one year.
Conditioning
Condition prospective breeders on varied foods, including live or frozen items such as brine shrimp. Keeping a group and allowing a pair to form naturally is the most reliable route to a bonded, productive couple.
Breeding Setup
- Dedicated breeding tank around 100 L with a sponge filter and dim lighting
- Soft, acidic water; temperature 28-30 °C (82-86 °F)
- A vertical or flat spawning surface (cone, flat stone or piece of slate)
- Quiet location with minimal disturbance
Spawning Behavior & Trigger
When ready, colours intensify and courtship includes circling and vibrating. The pair cleans a chosen surface and spawns, typically in the morning. Approximately 100-200 bright, sticky eggs are deposited on the surface.
Egg & Fry Care
Eggs hatch after about three days, and the larvae remain attached at the spawning site before swimming freely after roughly 5-7 days. Both adults produce a nutrient-rich skin secretion ("discus milk") on which the larvae graze for their first weeks. Parents stay close early on and gradually swim away, weaning the young off the secretion.
Common Challenges
Stable water chemistry is more important than hitting an exact numerical target; instability stresses developing fry. Forming a compatible pair can be slow, and inexperienced parents may eat early spawns before settling into reliable care.