Create a new rule called “Diving for Treasure” with the following text:

Each Fishing Contestant has publicly tracked nonnegative integer Depth (defaulting to 0) and integer Oxygen (defaulting to 20). When a Fishing Contestant’s depth is set to 0, their Oxygen is set to 20. As a Daily Action, Fishing Contestants may increase or decrease their Depth by 1. If a Fishing Contestant with a Depth greater than 0 has not already done so since the last Sight Disturbances, they may take the “Diving for Treasure” action, and it is the only action other than Sight Disturbances or Moving the Beast that they may take. Diving for Treasure is an atomic action with the following steps:
* Randomly select one of the following outcomes: Breathe, Treasure, Anomaly, or Nothing.
* If the outcome is Breathe: Reduce your Oxygen by your current Depth. If your Oxygen is below 0, increase your Madness by 2.
* If the outcome is Treasure: Follow the instructions in the subrule Treasures corresponding to your current Depth, if such instructions exist.
* If the outcome is Anomaly: Follow the instructions in the subrule Anomalies corresponding to your current Depth, if such instructions exist.
* If you are Mad, set your Depth to 0 and your Oxygen to 20.

Create empty subrules called “Treasures” and “Anomalies”.

Append the following to the end of the rule Madness:

* Diving for Treasure