Are there any foods I shouldn't feed my mouse?

Try to avoid fatty foods where possible, except for growing or convalescent animals, or where the food is otherwise very nutritious, such as sunflower seeds.

Peanuts are fattier and less nutritious than sunflower seeds, and provoke a skin reaction in some mice.

Chocolate may be toxic to rodents in large amounts, although I have not seen the research. There is no need to feed chocolate to mice anyway - they would prefer sunflower seeds.

Anything you wouldn't eat yourself because it might give you food poisoning - mice are susceptible to salmonella & other bacterial infections too!

Unwashed fruit/veg might carry pesticides etc. - wash or peel it first, unless it is organic. Washing/peeling will only remove surface residues, but it's all you can do.