I had a stained glass blank template of this fish, and I decorated it with various zentangle/doodle designs
I found another lovely website with a good collection of patterns to try, here's the link for other Zen artists - Pattern-Collections
I used WHS Spectrum Sings Pencils to colour the design, most of which was done in the weekly art class I attend.
Some patterns I find it quite easy to work out were best to add the darker colours, to give that lovely 3D affect.
I love how colour and shading affects the patterns