Trophic relationships in fish communities are affected by the availability of resources, which in turn is affected by spatial and temporal variations throughout the year. The aims of this study were to characterize the diet of A. tetramerus in a streamlet in the north of Brazil and compare its composition in different hydrological seasons (wet and dry seasons). Collections were performed every two months from October 2011 to September 2012 with the aid of seine nets, hand net and fishing traps in the streamlet located in the Machado River drainage basin in the Rondônia state. Most of the specimens collected were quite small (< 40 mm) and had empty stomachs. Our results showed that A. tetramerus feeds on a wide variety of items of plant origin, such as algae, seeds and leaves, as well as items of animal origin, including bryozoans, crustaceans, fish scales, terrestrial insects and detritus. The data also indicated higher consumption of aquatic insects than other food items, suggesting a primarily insect-based diet. Items of plant and allochthonous origin were consumed more in the wet season than in the dry season, but there were no seasonal differences in the consumption of animal and autochthonous items. KEYWORDS: Fish, Perciformes, Amazon, feeding habits, ornamental fish. Dieta sazonal de Aequidens tetramerus (Cichlidae) em um igarapé da bacia do rio Machado, Rondônia, Brasil RESUMORelações tróficas das comunidades de peixes são afetadas por variações espaciais e temporais, que alteraram a disponibilidade de recursos ao longo do ano. Os objetivos deste estudo foram caracterizar a dieta de A. tetramerus no igarapé estudado, bem como comparar se a composição dos itens da dieta desta espécie dependem da estação hidrológica (período chuvoso e seco). As coletas foram realizadas bimestralmente, de Outubro de 2011 a Setembro de 2012, com auxílio de picaré, puçá e covos em um igarapé localizado na bacia do rio Machado no estado de Rondônia. A maioria dos espécimes eram pequenos (< 40 mm) e tinham estômago vazio. Observou-se que A. tetramerus se alimenta de uma grande variedade de itens de origem vegetal, como algas, sementes e folhas; e de itens de origem animal como: briozoários, crustáceos, escamas, insetos terrestres e detritos. Constatou-se que há maior consumo de insetos aquáticos, o que sugere uma dieta insetívora. Itens de origem vegetal e alóctones foram mais consumidos na estação chuvosa do que na estação seca. Não houve diferença na composição da dieta dos peixes entre as estações de seca e chuva.

The aimed of the study was to evaluate the effect of continuous artificial aeration on zootechnical performance, hematological characteristics and glucose concentration of tambaqui (Colossoma macropomum) cultivated in a system without water flow. The study was conducted with two treatments, with aeration and without artificial aeration. Were 600 tambaqui juveniles with an average initial weight of 15 ± 0.15g were distributed in two excavated tanks. Thirty fish were captured per cultivation unit to perform monthly biometric measurements and were subjected to blood collection to determine hematological parameters. There was no difference between hematological variables (p<0.05). However, the continuous use of artificial aeration provided fish with more comfortable conditions, resulting in greater performance (p<0.05) in up to 90 days of cultivation, with an average daily weight gain of 4.82 g compared to 4.49g to the system without artificial aeration. It can be inferred that fish grown in a system without artificial aeration presented, when compared to those raised in a system with continuous artificial aeration, smaller values (p<0.05) of growth, both in weight and in length, consequently the continuous use of the aerator provided favorable conditions for the fish, resulting in average daily weight gain and total biomass gain.