Yes, gerbils can eat cooked rice. It provides carbohydrates, protein, and fiber and is low in fat. However, rice should be fed in moderation because it is high in starch, which can be difficult to digest and may lead to weight gain.
Feed no more than about 1 teaspoon of rice once or twice a week. Other suitable foods include seeds, nuts, grains, vegetables, and fruits. Avoid chocolate, coffee, alcohol, raw meat, onions, garlic, and chives. Consult a veterinarian with any dietary questions.