Lungworm larvae may be present in slugs and snails, and if eaten, pets may be infected with worms that make their way to the lungs, where they block airways and make breathing difficult. Most dog wormers don't claim to treat lungworm, although some cat wormers do. Research conducted internationally has found moxidectin, which is found in some heartworm treatments for dogs, to be effective against lungworm, but this claim can't be made for dogs on packaging in Australia. Check with your vet as to whether it's an issue in your area, and discuss the best preventative treatment.
To be a successful pet shop owner, manager or employee, you need to be able to sell merchandise, from pet food and toys to cages, fish tanks, leashes and the pets themselves. Obviously you need to know about caring for different animals in order to keep the animals you are selling in good condition; and advise customers on the products they might buy. Some pet shops may be more caring for the animals than others.