May be a strange question, but do FBT sleep?

My two fire belly toads like to rest on their rock islands or under a little rock cave. Thing is, they never close their pupils all the way no matter whether light is on or not. I work days and nights on a rotating shift so I have been home at all hours to check it out. How can I tell if they are asleep? Do they sleep or just rest?

Also, my fire bellies eat mini feeder guppies, meal worms, and gut loaded crickets. I feed the crickets carrots to enhance the toads belly color to the true red they are in the wild. Is there any other natural food I can give them that will enhance their color?