His real name was "Moose" and he was replaced by his son "Enzo" in the middle run of the show. He almost died in a dog shelter before he was rescued by the handler who trained him. His breed is a Jack Russell terrier and they can be a handfull to own or train but are super smart as most terrier's are. I was sad to see this today and what a life he lived. Fraiser was a wonderfull tv show and they just don't make them like that anymore.
BTW, in 2004 at the final tapping of the last show of Fraiser they had a curtain call for the cast and invited Moose. He was going deaf at the time but took his stage bow like a pro and a lot of the cators were touched by that. I remember reading that article and feeling a tear down my eye, it was touching, imo.