The smaller one is around three years old, the larger 5. These ages are not approximate, and are best guess from my vet. Low fat cat food is ok, I usually just dry Cat food and soak it in warm water. I don't feed them much of it, usually around three table spoons and that is it and I don't feed it too them every Friday. I mix it up with boiled chicken, fish, etc as well. Just remember, always a small amount to avoid pyramiding. You can also throw crickets in there, mine will chase them down. Just be sure to get them all out that they miss, cause crickets will harass them at night.