p2 question about p2 body and sprite position

[scofieldly]

hi all, 

I have a problem about the p2 body and sprite positon

when I enable a p2 body to a sprite, I use

fish.body.setRectangle(fish.width, fish.height);

to set the body shape, but the position of body is far away from the sprite, anyone know what is the problem? thx