Geophagus argyrostictus Breeding Guide
Breeding Geophagus argyrostictus, a Xingu eartheater that is a substrate-spawner rather than a mouthbrooder, with eggs hatching in about three days.
Overview
Geophagus argyrostictus is an eartheater from the Rio Xingu in Brazil. Unlike most of its congeners, which practise mouthbrooding, Seriously Fish reports that this species is a substrate-spawner adopting a fairly basic strategy. The note below records that this differs from the genus-level mouthbrooding assumption: follow the species source.
Sexing
Juveniles cannot be reliably sexed externally; during spawning the female's ovipositor is clearly visible. Mature males are slightly larger with longer fins, and dominant males develop a pronounced nuchal hump.
Conditioning
There does not appear to be any particular trigger for spawning. The main requirements are a good diet and a stringent maintenance regime involving relatively large weekly water changes.
Breeding Setup
- Soft sand with flat surfaces for egg deposition; a tank base of at least 150 × 45 cm
- Temperature: 26-30 °C (Seriously Fish maintenance range)
- pH: 6.0-7.5 (Seriously Fish)
- Hardness: 18-179 ppm (Seriously Fish)
- Large weekly water changes
Spawning Behavior & Trigger
Courtship involves fin flaring, circling, gaping and head-jerking displays. As a substrate-spawner the pair deposits eggs on a chosen surface; there is no specific environmental trigger beyond good diet and water management.
Egg & Fry Care
Up to 200-250 eggs may be deposited. Eggs hatch after approximately three days (about 70 hours at 27 °C). Fry accept good-quality powdered dry foods, Artemia nauplii and microworm as soon as the free-swimming stage is reached.
Common Challenges
This is a blackwater species requiring soft, acidic, scrupulously clean water, which makes it more demanding than many group members. Because eggs are guarded on the substrate rather than brooded in the mouth, they are more exposed to fungus and tankmates, so close attention to water quality and territory defence is needed.