If your snake is healthy it will be bright in colors and it's eyes will be clear (unless it's shedding!) if it's color is faded and it's eyes are smoky for more than a week or 2 it's probably sick. If it's skin is kinda lumpy that means it has mites go to a vet specialized in reptile care they'll tell you what to do you'll probably have to buy special tank cleaner you can find it anywhere. Your snake is usually happy just feed it weekly or every other weekly ;-)
and provide it with fresh water it'll be happy. You should "play with it" daily
and provide it with fresh water it'll be happy. You should "play with it" daily