Biotodoma cupido Breeding Guide
How to breed the greenstreak eartheater Biotodoma cupido, a biparental substrate-spawner whose fry are moved to a pit and guarded by both parents.
Overview
Biotodoma cupido is a peaceful eartheater from the Amazon basin, ranging from Peru through Bolivia, Brazil and Guyana, with much aquarium stock originating from Santarém. It is a biparental substrate-spawner that deposits eggs on rocks. Breeding is moderately challenging, and the species reaches sexual maturity at around 18 to 24 months.
Sexing
Sexual dimorphism is subtle and unreliable. Males tend to grow a little larger, are deeper-bodied, and develop longer filamentous extensions on the dorsal and caudal fins than females. Head-stripe patterns were once thought diagnostic but proved inconsistent.
Conditioning
Conditioning can simulate a seasonal change: alternate a stable phase with relatively few water changes against a phase of daily 20-25 percent water changes using rainwater or softened tap water, with increased turbulence. Many fish dig before they are mature enough to spawn successfully.
Breeding Setup
- Soft, acidic water, with incubation reported at 23-24 °C.
- Open, flat rock surfaces that a pair can clean and use as a spawning site.
- Fine sand substrate, since the species is a sand-sifter.
- Stability and good water quality, alternated with the conditioning regime above.
Spawning Behavior & Trigger
Females initiate courtship by digging pits, swimming head-down with darkened colouration, and lip-locking. The female cleans a rock surface by moving away the sand, then deposits the entire batch of eggs over several hours before the male fertilises them in a single pass — an unusual pattern in which the female lays all the eggs before allowing fertilisation.
Egg & Fry Care
The female tends and protects the eggs while the male patrols the surrounding area. Eggs incubate for 3-4 days at 23-24 °C; after hatching, fry remain in a prepared pit for about four days while absorbing their yolk sacs. Both parents then share guarding duties equally for a further six weeks, consistent with a biparental larvophile that relocates fry to pits.
Common Challenges
Immature fish often dig without spawning successfully, and soft, acidic water is needed for good results. The record lists this species as a substrate-spawner, matching the biparental substrate-spawning behaviour described by the source.