Russian blue cats are highly intelligent animals and require physical and mental stimulation, so it's important to give them access to toys at all times. They retain a strong hunting instinct, so a feathered fishing pole toy is the perfect plaything. Consider storing these types of toys in a cat-proof spot because: (a) your kitty will tear it to shreds, and (b) she may eat the feathers and/or the string, neither of which are good for her digestive system or overall health.
A cat may have rapid breathing for a variety of different reasons which may include infections, pain, high temperature (to cool down), heart failure among other causes; if your Veterinarian was unable to identify a cause, you should keep a close eye on Skittle and see if there is anything which occurs before an episode as it may be a reaction to anxiety from something. Regards Dr Callum Turner DVM
Give your Foreign Blue an adequate diet in the form of premium, dry cat food. You can spoil your cat from time to time and give him canned food that’s rich in protein. As they get older, dietary requirements may change, so it’s best to consult with a veterinarian for recommendations. When it’s time to change food, remember to add the new food gradually and mix it in the old one in the span of a few weeks or so. Make the transition too fast and your cat may get an upset tummy.
World War II nearly put an end to the breed. Very few cats survived the years of privation, and British and Scandinavian breeders turned to other breeds, primarily the Siamese and the British Blue, to help revive their bloodlines. Because of the Siamese influence, the cats developed a more extreme look, and the texture of their coat changed. It took years to bring the breed back to its original appearance. That was achieved by combining British bloodlines, which emphasized plush, silvery coats, and Scandinavian bloodlines, which were known for producing cats with bright breen eyes and flat profiles. The result was the Russian Blue of moderate type seen today.
Rapid breathing (tachypnea) is a respiratory disorder characterised by abnormal breathing that is rapid and shallow.  It is caused by a reduced level of oxygen, mechanical disorders (where the lungs aren’t able to expand as they should, usually due to a build-up of fluid in or around the lungs), and physiological disorders in which the cat’s respiratory centre in the brain is over stimulated.