The 24-hour continuous experiments are carried out in winter and summer respectively for the Zacco Platypus from the real river. The existence of the fish behavioral mode is confirmed, i. e., the fish lives with the mode of feeding and resting respectively for the daytime and nighttime in summer, while primarily with the resting mode for the day and night in winter. Based upon the results, the preference curves of water speed, depth and shield are plotted for each mode. The curves of speed are regressed with the normal distribution function. The favorable water depth for feeding is in the shallows of about 15cm deep, while for resting the more deep the water is, the preference shows more significant. As for the shield factor, the open water surface is preferred in the feeding mode, while the tendency of the preference to shield is found in the resting mode.