Great pet shop in Cabbagetown. They seem to have everything you would need for any pet you might have. Since I only have a dog I didn't venture into most of the store.
One key service they have here is that you can use their washing facilities to bathe your dog for only $10. There is a giant tub with a powerful sprayer and all the doggie bath products you could want (soaps, shampoos, conditioners, you name it). They also have towels and a hair dryer for drying off.
It's perfect if your dog needs a cleaning but you don't want to scratch your tub or have a fur explosion on your own bathroom. It's first come first serve, but if nobody is waiting in line they'll let you stay as long as you like.