In the present work we describe the larval development of Brycon amazonicus , with emphasis on structures linked to swimming, respiration and feeding. We monitored from larval hatching (13 h post‐fertilization) to juvenile stage. Formation of the oral cavity and differentiation of gill arches began within 4 h post‐hatching (hph) and within 11 hph the primordium of the pectoral fin appeared. At 25 hph, the head was in a rectili...