Aged Guinea Pig
Your guinea pig will probably be around quite a few years. In extreme old age, it may experience stiffness, loss of hearing and vision, and internal disorders.
Your pet will require more rest and tender loving care. The elderly guinea pig may become less adaptive to changes in the environment and food.
Even though you have developed a soft spot for it in your heart, if your guinea pig experiences pain or discomfort the humane thing to do is to put it to sleep and free it from misery.