This shows how I like to use Specular maps and diffuse maps instead of bump maps, although there is no reason not to use all three if the model calls for it. In this case, I’ve copied the fish Scale texture from one channel to the other.

It can be interesting to use different materials in each channel to create a more random grungy sort of texture.

If you are following the Step by Step tutorial, here are the steps in order:
Polygon Modeling
Joints
Cloner Object – Introduction
Cloner Object – Using Object Mode to animate
Target Effector
Optimizing Mograph Cloner for Display speed
Random Effector
Timeline
FCurve Offset to Delay Loop start
Specular and Diffuse Maps
Transparency Absorption
Refining Lights and Visible Volumetric settings