Snapper (Lutjanidae – mostly Lutijanus spp.) inhabit near-ocean reaches of streams throughout Costa Rica. They are generally marine, but will often feed in freshwater and it seems that they dominate the large, fish predator group in Costa Rican streams as a result. There are at least three common species in the Osa Peninsula, where these were found, including Lutijanus novemfasciatus (the black snapper or Pacific cubera snapper). Last year, we caught L. novemfasciatus in Rio Madrigal and recorded a new species for Osa.
I’m unsure of the identification of those below, but they were photographed in Rio Claro, near the Sirena Field Station in Corcovado National Park