LYNN – Brothers John and Rob Mellace along with sister Lucia Castle were barking up the right tree 15 years ago when the decided to open their own Lynn pet store.Today, that original store at 599 Lynnway is thriving – a leading dealer of healthy kittens, puppies, reptiles, fish and birds – and the family is marking its first anniversary this month with its Liberty Tree Mall store in Danvers.Rob worked for six years in the pet industry prior to launching Pet Express, and brought his brother and sister into the industry.?We started as a small family business with four employees, including ourselves, and today we employ 45,” said Rob Mellace. “Originally we started as a pet supply store only, but we became a full-line pet store with animals, grooming supplies and everything in between.”With the steady success of the Lynn store, Rob said Simon Malls, owner of Liberty Tree Mall and other malls in the region, pursued Pet Express to open the satellite store inside Liberty Tree in November 2009.?Simon Malls works with family type businesses because the mall has a family atmosphere with the movie theatre and food court,” he said. “They made us an offer we couldn?t refused and helped us expand.”Rob said the inventory in the 10,000 square foot Lynnway store and the 2,500 square foot store changes on a regular basis, and that Pet Express employees are constantly educated about the animals and new product lines of pet food or pet supplies.?When we sell an animal our goal is to make sure the customer keeps it at home, that?s why education is so important,” he said. “When customers buy from us, they?re buying from our family, and that?s part of why we?ve been successful.”Rob said the pet store does see a bump in business during the holidays, particularly because “everyone wants to get their pets a gift,” but added pet sales are fairly steady throughout the year.?The pet industry is an industry of love and companionship,” he said, adding that even in a down economy, “people will always want the companionship of animals.”Rob said Pet Express is preparing to open a third store on the North Shore next spring, but said it?s too early to announce the location.