During focal observations carried out in the Olho d’Água River, upper Paraguay River basin, Brazil, we registered the defensive behaviour of one pair of Crenicichla lepidota attempting to protect their offspring from conspecific and non-specific predators. Adults exhibited substrate-guarding behaviour and displayed primary and secondary anti-predation mechanisms. The primary mechanisms (e.g., fin flicking and flaring, gill extending) were ineffective against conspecific predators or against other species. Secondary mechanisms included charging would-be predators of the offspring, and this tactic was successful against non-specifics. This record confirms, in the wild, agonistic behaviour as an effective secondary defence mechanism used in parental care in Crenicichla lepidota.
