Prepare oatmeal and tuna.
Drain the oil from the tuna and set it aside.
Add water to a pot and bring it to a boil.
Once the water is boiling, add the oatmeal and stir over low heat.
When the oatmeal softens, add tuna, salt, and pepper, and mix well.
When all the ingredients are thoroughly cooked and the porridge thickens, turn off the heat.
Spoon the porridge into a bowl.