Game Problem

onClipEvent (load) {
    function reset() {
        this._x = 600;
        this._y = random(200)+100;
        sharkspeed = random(4)+1;
    }
    reset();
}
onClipEvent (enterFrame) {
    if (_root.fish.scrollStart) {
        this._x -= +_root.mainGround.groundSpeed;
    } else {
        this._x -= sharkspeed;
    }
    if (this._x<-10) {
        reset();
    }
}

See that code there is supposed to make my enemy quite fast at times since it is random.’

But it goes very slow when i start moving my fish and start scrolling.
Could you [please tel me why

GroundSpeed = 10
Shark Speed = Random of course
And the FPS = 25

it all seems to be fine please help me if you need the fla badly ill give it to you

i had this problem before can i see the fla?