Board Game Arena

The rules say that the game ends when there are no more corals in the bag, but that's not how it works. Once the bag is empty, you seem to continue play until ... I'm not sure? Not just one more turn per player (we had more than one turn left), not just until everyone had surfaced, but perhaps until there are no more corals in the nursery? Or perhaps until noone can buy more corals from the nursery, due to lack of money or corals?

The rules say: "The game ends when the underwater nursery is empty and can no longer be refilled."