Because the tail is made up of a series of hinges, each with only one degree of freedom, the tail rig has a joint at the pivot of each hinge.
Each joint then had two of the rotate axes locked, so it can only rotate in the same direction as the model hinge.
Add a IK Spline Handle and control clusters
|IK Spline Settings|
IK Spline is now constrained so its motion matches the limitations of the model
The same technique was used to rig the spine