Experiment two was designed to determine the ingestion of marble goby fingerlings of different sizes on prawns during daytime (07:00–17:00 h) and nighttime (17:00–07:00 h).Marble goby fingerlings of different sizes (0.26±0.01, 0.34±0.02, 0.52±0.05, 0.87±0.04 and 1.43±0.08) were stocked at a density of 10 gobies per aquariumfor each size group, while 200 prawns per aquarium of 9–12 mm in total length (determined in the experiment one) were used in this experiment.