Geophagus sveni Breeding Guide

How Geophagus sveni, a member of the G. surinamensis group, reproduces as a substrate-spawning, biparental mouthbrooding eartheater.

Overview

Geophagus sveni is a South American eartheater native to the Tocantins River drainage in Brazil, reaching around 225 mm (10 in) standard length. Seriously Fish lists it as one of thirteen described members of the Geophagus surinamensis species group. Members of this group are substrate-spawning, biparental mouthbrooders, so the breeding behaviour described here reflects that of the surinamensis-group assemblage to which G. sveni belongs.

Sexing

Within the surinamensis group, no reliable external differences between the sexes have been observed except during spawning, when the female's ovipositor becomes visible. Because accurate sexing is essentially impossible beforehand, the recommended approach is to start with a group of juveniles and allow pairs to form naturally.

Conditioning

Fish in the group take at least a year to reach sexual maturity. Good nutrition combined with rigorous maintenance and substantial weekly water changes acts as the primary spawning stimulus. A sandy substrate that the fish can sift is appropriate for this benthophagous eartheater.

Spawning Behavior & Trigger

Spawning begins on a substrate surface such as a flat rock or piece of driftwood, which the pair clean and defend. Courtship in the group involves fin flaring, circling, gaping and head-jerking displays. The female deposits one or more rows of eggs that the male then fertilises, the process repeating numerous times over a period of several hours.

Egg & Fry Care

After the substrate phase, the adults take the eggs or larvae into the mouth for continued incubation, with both parents typically sharing brooding duties in this group. At 25-28 °C the fry of surinamensis-group species become free-swimming at roughly 8-11 days old and readily accept powdered dry foods, Artemia nauplii and microworm. The parents shepherd the fry, drawing them back into the mouth when danger is sensed.

Common Challenges

The chief difficulties are obtaining a compatible pair from a group given the lack of external sexual differences, and the long maturation period. As with related eartheaters, stable, well-maintained water and ample space are needed for pairs to settle and brood successfully.