In recent years, considerable research interest in behavioral ecology has focused on characterizing and understanding individual differences in behavior that are consistent over time and across contexts, termed animal “personalities,” and correlations between various behaviors across contexts, termed behavioral syndromes. Although there is some evidence that differences in personality among individuals within populations can be genetically based and adaptive, when and how individual personality differences emerge in a population is not well understood, but of considerable general interest. Here, using juveniles of the convict cichlid (Amatitlania siquia) as a model system, we investigated in the laboratory whether individuals consistently differ in their personalities and whether behavioral syndromes are apparent at an early developmental stage and, if so, whether distinct personality traits are heritable. Under standardized laboratory conditions and using sibling analysis, we quantified interindividual differences in their boldness behavior under potential predation threat and their exploratory activity in a novel environment, 2 ecologically important behaviors, as our focal personality traits and estimated their respective repeatability and heritability. We report for the first time consistent (repeatable) and heritable individual differences in boldness and exploratory behaviors, and a boldness–exploration behavioral syndrome, in young convict cichlids. Bolder fish were more exploratory than relatively timid ones. These results provide novel evidence for the emergence in early life history of consistent individual differences in personality traits and behavioral syndromes in this species and suggest that genetic variation for boldness and exploratory behaviors, and thus potential for selection on these traits, exists in our study population.