I have been drawing lots of mermaids and fish, and even a few geckos. Here are some scales brushes that I made and found useful. You are free to use these for anything you like but please don't sell them :) fish scales snake scales lizard Arty Shrew's Scales Brushes
17 Snake, lizard and fish skin textures and scale brushes for adding that reptilian touch to your images snake fish skin Scales Brushes