Need seawater with appropriate salinity and bait in seawater, which is generally impossible at home.

Is your home near the seaside? If you are at the seaside, put it on a stone in the sea. If you don't get close, you must raise it with seawater or salt water. However, oysters cannot be kept in seawater or salt water for a long time, because there is no plankton (nutrition and food) needed by oysters in these waters. Three or five days at most, and then you will lose weight and die slowly. What a pity!