According to the Rat and Mouse Club of America , Fancy Rats who enter rat shows have to meet standard conformation requirements. Details of Standards and conformation for USA can be found here . Please note that rat standards in one country doesn't necessarily mean they are the same for any other country. Please check with your respective rat clubs for more information. Pictures are taken from the altpet.net website.
Colors Here is a list of rat colors.
Other Colors - Agouti , Amber , Blue Agouti , Chinchilla , Cinnamon , Cinnamon Pearl , Fawn , Lynx, and Pearl. Silvered - Silver Black, Silver Fawn , Silver Lilac , Silver Mink, and Silver Chocolate. Any Other Color Pattern - Himalayan, Siamese , Blue Point Siamese , and Merle. Markings Show quality rats usually has very good markings, but a majority of the pet rats are often not bred for their markings, so you will not usually see perfect markings. For example, a hooded rat should have their colored stripe go all the way from their necks to the base of their tails.