My object won't destory

using UnityEngine; using System.Collections;

public class Arrow : MonoBehaviour {

 public int Direction = 1;
 private Vector2 vel = new Vector2(6, 0);
 
 void Update() {
     vel = new Vector2(6 * Direction, 0);
     rigidbody2D.velocity = vel;
     if(Direction == -1) {
         transform.rotation = Quaternion.LookRotation(new Vector3(0, 0, -44 + 180));
     }else{
         transform.rotation = Quaternion.LookRotation(new Vector3(0, 0, -44));
     }
 }
 
 void OnCollisionEnter2D(Collision2D col) {
     if(col.gameObject.tag == "Enemy") {
         Enemyhealth eh = col.gameObject.GetComponent<Enemyhealth>();
         eh.Health--;
     }
     
     if(col.gameObject.tag == "Destroyable") {
         Destroy(col.gameObject);
     }

     Destroy(gameObject);
 }

} I tried putting a box collider and it still wont destroy. Plus I tagged it Destroyable.