vertices stuck on axis I made a model (of a fish) using x-axis mirroring. Some vertices sit on the x=0 plane. I extended a selection of vertices on the mirror plane to make the back fin of the fish (see image). Now I want to give the fin a little more thickness by pulling the fin vertices out of the mirror plane. However, Blender doesn't let me move these vertices (e.g. the one selected in the image) along the x-axis. I disables clipping in the mirror modifier, even deleted the mirror modifier alltogether but still, when I hit 'G' for translate, and then 'X' to limit translation to the x-axis, the vertex doesn't move. (movement along other axes works, and other vertices of the model that are not on the mirror plane move just fine).

What else besides deactivating the mirror modifier do I have to do to release the locked x-axis translation?
In Edit Mode. Press T to bring up Tools Menu on the left hand side. Click on 'Option' tab and see if X-Mirror is check. Simply uncheck it.