Help on fish demo tutorial

I am on the part where it tells me how to make the fish move at random speeds. The problem is that when I script it in and run it, the fish doesn't even move! I have set up the dynamic fields correctly and I know the code is correct but when I start the game it doesn't move. I even used the echo command and typed in %this.minSpeed and it always returns 1 and not the value its set to. Can anyone help me?