Black-throated Eartheater

About

Known in Australia as the black-throated eartheater, this cichlid from the Corantijn and Nickerie river drainages of Suriname belongs to the sprawling G. surinamensis group. A cluster of closely related species that has caused no shortage of confusion in the hobby. Geophagus brachybranchus can be picked out by a combination of features: dark preopercular markings, a blackish exposed branchiostegal membrane, and in adults a reddish caudal fin patterned with large spots. Flanks lack vertical barring even under stress, which helps separate it from lookalikes. Despite being labeled aggressive on paper, this species is far more civil toward tankmates than that tag implies outside of spawning. It is gregarious by nature and does best kept in groups of five or more, where a clear dominance hierarchy forms and individuals settle into predictable social roles. Smaller groups often result in weaker fish being harassed relentlessly. Suitable company includes most peaceful species that share its preference for soft, acidic water. Hard-water species and territorial bottom dwellers are poor fits. Breeding is genuinely fascinating: pairs are larvophilous mouthbrooders that spawn on flat surfaces and take fry into the mouth within days of hatching. The species remains relatively rare in most markets outside Australia, and juveniles sold as G. surinamensis are frequently something else entirely.