Fig. 5. Seasonal changes in the proportional composition of food items within stomachs of Symphysodon haraldi from blackwater habitats of the Tefé region. Calculations of mean food item contribution excluded specimens with empty stom- achs. Error bars (displayed above bars) refer to one standard deviation from mean. Algae = periphyton identified as a mass of bright green filamentous structures. FOD = Fine organic detritus. GPM = green plant (macrophytes) matter – apparently mostly small triturated pieces of leaves. Periphyton, FOD and GPM were difficult to separate volumetrically, and are there- fore combined into a single category. GPM represented only a small portion of the volume of this category (perhaps less than 15%). COD = Coarse organic detritus – mainly pieces of wood and bark.