Fishing This is an extremely popular game with rat lovers around the world. I think mostly because it is just so darn fun to watch! First you need a pan or bowl, something large and sturdy which you can fill with water and doesn't tip over. Large, heavy plastic dog dishes work well for this. Fill the bowl with tepid water and add peas. The first time you introduce it to your rats, only fill the bowl about an inch deep or less. This makes it extremely easy for your rats to grab the peas and it allows them to learn how to play the game. After they get use to it and learn to master it, you can start slowly adding more water, making the game more difficult. You might even have a rat willing to take a dive completely underwater for a tasty morsel or two.