This scale texture is very satisfying and tedious. I begin by making various size balls of clay, pressing them onto the sculpture in a random cobblestone-like pattern. Then, working a small section at a time, I use a needle tool to push in a straight line where the circles overlap—transforming the round edges into geometric scales. The last step is to take a small silicone tool with a wedge shape to blend and soften the edges and remove any gouges from the needle tool.
Here’s a video showing one section of scales on the tail.