Nearly six out of 10 U.S. households own a pet, and while cats and dogs are still the most popular animal companions, fish, reptiles and even more exotic creatures are increasingly common. Our love affair with pets is fueling a booming industry. Americans spent more than $9.3 billion last year just on food for Fluffy and Fido, and billions more on toys, grooming tools and myriad other pet accessories - from preservative-free pet food and organic flea treatments to carpet- covered gym sets for cats and plastic exercise ramps for gerbils. But there's a darker side to pet ownership. Animal shelters still euthanize millions of “throw-away” pets each year. Meanwhile, local officials are worried about controlling vicious dogs, banning ownership of more exotic animals and balancing the rights of pet owners and the rest of the community.