Sick Cat Symptoms - How to tell if your cat is sick

when your cat is sick, it can't tell you so it's up to you as a pet owner to train yourself to be observant. A good indication that a cat has a temperature, is that its ears are hot. A rectal thermometer is needed in order to take a precise temperature reading, which should be 38-38.5°C. Unless you have been taught how to do this properly, you should let your vet do it. You should check your cat regularly to make sure it is in good condition. Eyes, Ears, Nose and Mouth: The eyes of a healthy cat are clear, bright and free of redness or discharge. The nose should be cool and moist, with no secretions. The ears should be clean and dry, with pale pink skin inside and on the external flaps, and there may be a small amount of clear or dark wax in them.

The mouth should have pink gums and lips, and the breath should be free of odor. If your cat's eyes are red, have a cloudy or mucus discharge, are coated with film, or if your cat has an increased sensitivity to light or is squinting, it may have an injury or infection and should be checked over by your veterinarian. A small amount of dried mucus in your cat's eyes is normal, the equivalent of sleep in human eyes. There may be more or less sleep at times because of dust, dirt, smog or other irritants in the air.

If your cat has bad breath, it may have a digestive disturbance, infected teeth or gums, or a urinary ailment.

Coat And Skin: Your cat's coat should be unbroken, smooth and soft to the touch. Its skin should be clean and free of sores, rashes

If cat are exposed to fleas, they may become anemic. Cats can also develop an allergy to flea bites, resulting in excessive scratching or possibly skin disease. Finally, humans are also susceptible to itchy flea bites, usually on the ankles.
If your cat does not eat/drink anything for 2 days, bring them to the vet immediately for an examination.
The most common symptoms of vitamin and mineral deficiencies in cats are lethargy and apathy. If your cat is unusually tired and loses interest in exercise and regular daily activities, this could be a sign that your pet is unhealthy, possibly undernourished.