Navigate to the tail in Textools or Penumbra, and each material is a different part of the tail. The first material is the scales on the tail, you can change Row 16 to pick any colour you want! The second material is the see thru fin which you can also change to any colours you wish. It has a gradient so you can put one colour into Row 15, and one into Row 16 and make a gradient 2 colour fade, or change both rows to the same colour for a single colour look! It is very customizable!