To take advantage of the abundance of both fishery and wave energy resources in offshore sea areas, a novel floating platform with a heaving buoy-based wave energy converter (WEC) assembled with a set of net cages is presented in this work. The floating WEC system provides a power supply, while the net cages are used for aquaculture. It is designed to have an independent and self-operation breeding function. An experimental study is carried out to investigate the hydrodynamic performance of the device in a wave tank considering the factors of net cages, draft depth, and power take-off, and results show that these variables have significant effects on wave energy capture. Incident waves with short periods cause intense interactions that allow the device to undergo large relative motion. The draft depth could be determined according to wave period rather than wave height. This study also explores the response amplitude operator of the device and determines its resonance scope. The experimental results could provide reliable information for future studies on phase differences and the design of two-body WECs.