Schooling behavior by two stream fish in Brazilian semiarid

Shoaling can provide a number of advantages for individual fish, enhancing
foraging efficiency and reducing predation risk. We investigated the role
of multiple characid species shoaling (Compsura heterura and Serrapinnus
piaba) in order to recognize social behavior, foraging strategy, and diet
composition in one semiarid stream, Northeast of Brazil. The study was
done by field observations (ad libitum). The most frequent social
behavioral (Arranged Mixed-species school - 38.46%) was represented by
mixed-species schools structured with large-sized individuals of C.
heterura using the school periphery and small individuals of both species
using the center of the school. Shoals with lower individuals inhabiting
shallow locals and pools presented higher frequency of this behavior.
Although foraging behavior did not vary significantly between the two
species, each characin species explored distinct food resources,
indicating that diet segregation can act as a strategy to both species
foraging in the same shoal. These results suggest that C. heterura and S.
piaba have mechanisms to facilitate their coexistence in structured
mixed-species schools, minimizing the costs of living in groups.