Geophagus parnaibae Breeding Guide
Breeding Geophagus parnaibae, a Rio Parnaiba eartheater that is an ovophilous biparental mouthbrooder bred on numerous occasions in aquaria.
Overview
Geophagus parnaibae is an eartheater endemic to the Rio Parnaiba drainage in Brazil, where FishBase records it over bare sandy bottoms in brooks and small rivers with strong current during the rainy season. According to Seriously Fish it is a substrate-spawning, ovophilous, biparental mouthbrooder that has been bred on numerous occasions in aquaria.
Sexing
Accurate external sexing is essentially impossible except during spawning, when the female's ovipositor is visible. The recommended approach is to start with young fish and allow pairs to form naturally; sexual maturity can take at least a year.
Conditioning
No specific trigger has been identified. The main requirements are a good diet and a stringent maintenance regime with relatively large weekly water changes. FishBase notes a strongly herbivorous, omnivorous diet in the wild, so a varied plant-inclusive diet suits conditioning.
Breeding Setup
- Soft sand with rocks or driftwood as spawning sites; a tank base of 100 × 45 cm or more
- Temperature: 24-31 °C (FishBase environmental range)
- pH: 6.5-7.6 (FishBase)
- Large weekly water changes
Spawning Behavior & Trigger
Courtship is relatively unobtrusive, consisting of fin flaring, circling, gaping and head-jerking displays. Pairs select and defend spawning sites on rocks or driftwood, with the female laying eggs in rows before the male fertilises them. No particular environmental trigger is required.
Egg & Fry Care
Maximum brood size is around 200 eggs. Both parents participate in mouthbrooding duties, either simultaneously or by exchanging the entire brood on a roughly daily basis. At 25-28 °C the fry become free-swimming at 8-11 days of age and readily accept powdered dry foods, Artemia nauplii and microworm.
Common Challenges
Sexing requires a group to obtain a compatible pair, and maturity is slow. The species tolerates harder water than blackwater congeners but still needs a stable, clean environment and soft sand for natural foraging behaviour.