PS it work much better when you put the fin on front wards .
turned the fin 180 & it works much better
You mean you turned it opposite from your picture, so it is turned like on a TT ?
Yes, the fin has a round leading edge (at the diagonal so to speak), and usually sharp at the trailing edge - so for the yaw stabilisation to be good and smooth, it has to be turned that way.
Althoug - a "rudder" as it is here, would be even better (more stabilisation less drag) if it was turned exactly like your picture, just with a sharp TE and a round LE (which is the opposite of what TT fins are...)
But it is so small, that it really does not matter - as long as it is not too sharp at the LE (no matter how it is turned), which will work worse