The fauna that Morisot and Chaffanjon encountered during their trip up the Orinoco was part of the river’s complex and diverse ecosystem. Morisot’s sketches and watercolors documenting the animals living along and in the Orinoco, which mainly focus on colorful river fish, display his desire to capture them with scientific accuracy. He annotated his watercolors with local names for the species, such as ‘vieja loca’ or ‘crazy old lady’ in the case of the striped Orinoco angelfish. In his diaries, Morisot described the physical appearance of the fish in great detail. Deliberately using language that was understandable to European readers, he likened the features of the flagtail fish to that of a carp, or the face of the black spot piranha to a bulldog. In his journal, Morisot also dramatically recounted the perils of traveling along the river, describing how the piranha could bite chunks of flesh “the size of a twenty franc coin,” around one inch, or the behavior of the electric eel.