Um, it really depends. I know you can buy either canvas's made for watercolors or a ground that you apply to a canvas before painting, but personally I would use a good quality paper of about 300 gsm. Canson is usually quite cheap in comparison to Arches and the likes!
Thank you so much! I wanted to do this painting with water colors but might just do it on my watercolor paper. I'll need to get some more. btw I really love the tiger painting you did, the ACEO one.