Many other creatures other than cats and dogs can be kept as pets. The RSPCA provides information on basic care of some not covered here. Be very wary, however, of buying exotic pets, including some species of parrots. Illegal trade in exotic species endangers biodiversity – and is also horrific for the individuals involved: typically several will die during capture and transportation for every one that ends up on sale (source: WWF UK).
The RSPCA state “Anyone in charge of, or in control of, an animal has a duty of care towards it. This duty of care should include providing the animal with suitable accommodation, an adequate diet, protection against disease, pain and injury and ensuring that it can exhibit normal behaviour.” This applies as much to fish, frogs, stick insects, and other exotic pets as to cats and dogs.