Always make sure, however, that any change you make in the animal's environment is a safe one. When you give them a cardboard tube or a nylon bone, you are helping to satisfy this natural inclination. Such enrichment devices are also safe. Mice build nests, so giving them tissues, gauze, or a cotton pad is a safe way to satisfy this behavior. Hamsters, which like to run on treadmills and climb for many hours at a time, should be provided with a treadmill, habit trail, ladder, hiding place, or shelf.
Fish spend hours swimming among rocks and plants.
By adding these items to an aquarium, you are creating a more natural environment. A ball to roll around Branches to climb Food puzzles to forage Plastic piping to climb, run through, and hide in Nutritious food treats. One of the best ways to prevent loneliness is to keep two or three animals of the same species together. Unless you are prepared to handle babies, only animals of the same sex should be housed together. Some animals, like male rats, fight and should not be kept together.