Water samples, zooplankton community and sediment samples were analyzed at three sites in a pond receiving wastes, bi-weekly for seven months, covering the rainy and dry seasons. Water quality parameters failed to show significant differences between the sites for turbidity, total suspended solids, dissolved oxygen, transparency, conductivity, alkalinity and total phosphorous. Only temperature was different between the seasons. In the case of sediment, only aluminum (Al) was not different during the experimental period when highest calcium (Ca) concentrations were reported. The relative abundance of Rotifera during the sampling period reached 80-96% (rainy season) and 59-98% (dry season) in total zooplankton. Current study demonstrated that the water quality of shallow pond associated with allochthonous materials from aquaculture farm significantly influenced the structure of zooplankton assemblage due to high nutrient concentrations, conductivity, alkalinity and chlorophyll-a causing more fertilized water. However, heavy rains (February-April) and continuous water flow favored aeration (dissolved oxygen >5.2 ± 1 mg L-1). The use of pond water for agricultural irrigation or for other purposes, must be analyzed more effectively, avoiding problems caused by its usage.

Current study evaluates the macrophyte biomass of water hyacinth, Eichhornia crassipes, in diet food to improve the growth and survival of angelfish, Pterophyllum scalare. The liquid (extract) and ground modes are employed. Specific growth rate, weight gain, feed intake and final body weight in basal diet and macrophyte extract biomass diets were similar (p > 0.05). Fish survival was high in all dietary treatments (> 90%), while survival percentage of 100% was reported in ground macrophyte biomass treatment. Ground macrophyte biomass may be included in the diet of P. scalare up to 5%. The inclusion of E. crassipes in the diet of P. scalare proved similar or better results than basal diet. The macrophyte proved to be a food strategy in angelfish diets that may be implemented in the species's diet at 32% levels of crude protein. The latter, easily found in tropical regions, affects directly the species's growth and survival rates.