Guinea pigs need a lot of vitamin c in there fruits and veggies. But some are poisinous. But give it parsley, potatoes, apples with skin but no seeds, tomatoes without seeds or stems,ocaisonally banana, balck berries, blueberries, strawberries, cabbage,carrots,celery (cut small and take out the stringy stuff), lemons, limes, and seedless grapes.ect ect hope this helped.
The mainstay of a guinea pig's diet should be timothy hay and a high quality pelleted diet. Fruits should ideally not be fed to a guinea pig--they are high in sugar and do not promote healthy intestinal bacterial flora. Good vegetables to feed are bell peppers, collard greens, mustard greens, parsley, kale, and broccoli leaves. Treats should be fed sparingly. Vitamin C needs to be supplemented-the best way to do this is via oral tablets. Water should be available at all times.