how do i check if the player stop moving/decrease speed/stop moving distance so i could stop the scroll animation background at the back.

i have a 2d game with this problem taking up all the time.. i know its simple to you guys. but i cant seem to find a way to check so i could stop the animation of the background, ive used GM.Player.rigidbody2d.velocity.magnitude == 0, initialdistance > distance, and many more.. i probably am doing something wrong with my code..can anyone help me?

this is the code for the background scrolling.

 public class ScrollMidBackground : MonoBehaviour {
     public float speed = 0.03f;
     private GameManager GM;
     private float initialDistance = 0f;
     
     void Start()
     {
         GM = GameObject.FindGameObjectWithTag ("GameController").GetComponent<GameManager> ();
     }
     void FixedUpdate () 
     {
             if(GM.taptostart==true)
             {
                     transform.Translate (speed*-1, 0 , 0);
             }
 
 
         if(GM.isGameOver)
         {
             speed = 0.0f;
         }
 
     }
 }

// ive deleted all the codes concerning on stopping the movement with the use of my previous codes above.