Ferrets are strict carnivores, so they need to be fed on a good quality meat-based food. Due to their high metabolic rates food should be available to them at all times.
Previously owners were advised to give dry complete kitten food to their ferrets, and you may still see reference to this advice in ferret books. There are now complete ferret diets available, which are balanced to meet the nutritional demands of your ferret depending on it's age, health status, level of activity and reproduction status.
It is thought that ferrets cannot digest large amounts of fibre or starches. It is therefore advised not to feed bread or cereals to your ferret.
Make any changes to their diet gradually as a sudden change can upset their digestive system.
To help prevent obesity only give your ferret treats in small amounts. Ideally you should use treats specially formulated for ferrets, but you can give cat treats if these are unavailable. Tiny bits of raisin, grape and banana can be given as an occasional treat.
Some ferret books still advise offering birds, chicks, mice etc. alongside their normal diet. With the development of specialised complete ferret foods it is no longer necessary to include these in their diet, and since they can transmit parasites and infections they are best avoided.
If you feed a high quality complete ferret food you should not need to give additional vitamin or mineral tonics. Some tonics can be toxic in high doses, use them only on the instruction of a veterinary surgeon.
Change water daily. Ideally use a gravity water bottle which delivers a small amount of water when the ferret licks at the spout. Water dishes can become easily contaminated but if you do choose to use one select a heavy dish which can't be easily knocked over.
Disinfect the water bottle weekly in a sterilising solution suitable for babies. Follow the instructions carefully and rinse thoroughly before use.
If your ferret lives outside a water bottle cover is advised to help limit algae growth in summer and help prevent the water freezing in the winter.