What is the difference between a blue heeler and red heeler?

Australian Cattle Dogs and Blue Heelers are the same thing. 'Australian Cattle Dog' is it's official name, but we (In Australia) often call them blue or red heelers for the colour of their coat and their ability to 'heel' cattle. There are however 2 breeds of Bluey (we shorten everything in Aus, it's got a nickname for the nickname). One is the Australian Cattle Dog and the other is the Australian Stumpy-Tailed Cattle Dog. They look pretty much the same, except for the obvious; one has a short tail.