The four most common colorings of Aussies are blue merle, red merle, black tri, and red tri. Aussies can come in many other colorings as well, such as solid red, or solid black; all can occur with or without white markings, tan (called "copper") points, or both. Dogs with tan and white along with the primary color are called tricolor. Dogs with white or copper only along with the primary color are called bi-color. Too much white on any Aussie is a serious flaw, because it is frequently accompanied by deafness and/or blindness, which can occur when two merles are bred together (the double merle) or when pigmentation doesn't cover the ears or eyes on any other breeding. A hallmark of the breed is a short bobbed or docked tail in countries where docking is permitted. Some Aussies are born with naturally short bobbed tails, others with full long tails, and others with natural partial bobs, where the tail is midlength and appears stubby. Most breeders dock the tails when the puppies are born.
Generally the breed is an energetic dog that requires exercise and enjoys working, whether it is learning and practicing tricks, competing in dog agility, or any other physically and mentally involving activity. It is usually a sweet and affectionate dog who is faithful to its owners and may be good with children, although its overwhelming instinct to work may subvert its ability to function as a family dog.