Celery may seem like a nice fresh vegetable to offer your rodents, but it carries two dangers. First, celery contains high amounts of sodium. If an animal ingests too much sodium, it can end up bloating with water. Water retention may lead to other health problems. In addition, celery is a choking hazard because of the long strings in it. You can avoid this problem by offering very small bits of the vegetable, but it’s best to limit the amount your pet eats.