Mices are especially fond of bananas, avocado, broccoli and corn-on-the-cob. Give oily seeds and nuts sparingly. Given sparingly, grain treats such as dry low-sugar cereals, plain popcorn, wild bird seed, and dry oatmeal will be enjoyed by your pet rat or mouse. Never give a mouse sweets or chocolate.
Contrary to popular belief, mice do not even like cheese, although it can be given. Mice also love the running wheel, just like hamsters. They love them and are unwilling to leave the wheels till they are totally worn out & are about to doze off, or about to eat.
A Note About Water
Many small animals can survive without water for long periods of time, however, they will not be as healthy and their life span will be shortened. They will be thinner, their coats will not be as healthy, and they will be much more aggressive without water. Although you may give your pet vegetables and fruits as part of its diet, they are not a replacement for providing fresh clean water every day. Always provide your pet with fresh water.