Estratégias alimentares do peixe-folha, monocirrhus polyacanthus (osteichthyes, nandidae), e descrição anatômica dos estádios pré-adultos da espécie

Abstract

The leaf fish (Monocirrhus polyacanthus) is one of two representatives of the family Nandidae in South America, which also has freshwater representatives in West Africa and Southeast Asia. This work aims to describe the developmental stages of pre-adults of M. polyacanthus and the feeding habits of the species, respectively, through the analysis of samples from alcohol-fixed pre-adults and the feeding behavior of adults kept in the laboratory. Based on samples taken at the 3rd, 7th, 53rd and 180th day after hatching, three developmental stages of the pre-adults were analyzed, noting in each one in relation to the next an accentuated development of certain structures, such as mouth and tail, in comparison to others, such as the eyes. As for feeding behavior, it was observed that prey is obtained by suction, from a pressure gradient generated when the mouth is opened. Contrary to what was reported by Liem (1970), M. polyacanthus also feeds on other prey Aue not fish, which are ingested regardless of their position in relation to the predator. However, the leaffish showed a preference for fish species that live in the water column over those found on the surface and bottom, or even the non-phytic organisms on which it also feeds.