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 aquarium for 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.