Oh wow I thought this was a silicone tail! Very very nice fabric tail. Now this really makes me want to make my own fabric tail. I knew there had to be some example out there of a nice fabric tail that wasn't just solid fabric.
sorry it's taken me so long to get back to you--there are some ridges in the middle, but the paint stiffened the fabric a bit so they're not too obvious. I also trimmed some of the ridges on the edges of the fin so I could extend it, but be warned that this decreases the stiffness/thrust of the fin and cuts down on propulsion while swimming.
And yeah, while I actually like blue/green better as colors on their own, I think the orange/red/gold tones work better for me in a tail (: It provides a nice bright contrast with typically blue/green or darker water.