Wet tail is a very common disease in hamsters, unfortunately many hamsters will die once they are infected and vets often can't save your pet. If you do notice any of the symptoms I would advise you got your pet straight to a vet to be treated.Take the hamsters food away to rest the guy and aim to clean the cage every 3 days. Make sure your hamster keeps warm, vets will usually treat your pet with antibiotics.
The symptoms: Wet tail end and/or abdomen. Often Smelly due to a watery diarrhoea. Signs of abdominal pain or hunched appearance. Often hamsters stop eating.