How can I make my melee attack hit multiple prefab enemies?

I have my game set up and it seems to work fine when I melee combat the enemy I created. It's takes 3 hits and dies like I would expect.

I can't seem to damage the prefabs that I spawn on the level.

I can duplicate the Enemy gameObject, but then only the most recent duplicate will take damage and be affected by animation controllers.

I think it has something to do with my AttackTrigger c# script not targeting multiple enemies?

Here are my scripts

"Player Attack Script:"

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityStandardAssets.CrossPlatformInput;
 
 public class PlayerAttack : MonoBehaviour {
 
     private bool attacking = false;
 
     private float attackTimer = 0;
     private float attackCooldown = 0.3f;
 
     public Collider attackTrigger;
 
     private Animator anim;
 
     void Awake (){
         anim = gameObject.GetComponent<Animator> ();
         attackTrigger.enabled = false;
     }
 
     void Update (){
         Attack ();
     }
  
     void Attack () {
         bool isAttacking = CrossPlatformInputManager.GetButton ("Attack");
 
         if ((isAttacking) && !attacking)
         {
             attacking = true;
             attackTimer = attackCooldown;
             attackTrigger.enabled = true;
         }
 
         if (attacking)
         {
             if (attackTimer > 0) 
             {
                 attackTimer -= Time.deltaTime;
             }
             else
             {
                 attacking = false;
                 attackTrigger.enabled = false;
             }
         }
         anim.SetBool("isAttacking", attacking);
     }
 }

"Player Attack Trigger Script:"

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class AttackTrigger : MonoBehaviour {
 
     public int attackDamage = 10;   
                       
     GameObject enemy;
     GameObject enemies;
     PlayerHealth playerHealth;                  // Reference to the player's health.
     EnemyHealth enemyHealth;                    // Reference to this enemy's health.
     bool enemyInRange;                         // Whether player is within the trigger collider and can be attacked.
     float timer;                                // Timer for counting up to the next attack.
 
 
 
     void Awake ()
     {
         enemy = GameObject.FindGameObjectWithTag ("Enemy");
 
         enemies = GameObject.FindGameObjectWithTag ("Enemy");
 
         enemyHealth = enemy.GetComponent<EnemyHealth> ();
     }
 
     void OnTriggerEnter (Collider other)
     {
         if(other.gameObject == enemy)
         {
             //Debug.Log ("I Touched " + other.name);
 
             enemyHealth.TakeDamage (attackDamage);
 
             if(enemyHealth.currentHealth > 0)
             {
                 enemyHealth.TakeDamage (attackDamage);
             }
         }                
     }    
 }  
 

"EnemyHealth Script:"

 using UnityEngine;
 
 public class EnemyHealth : MonoBehaviour
 {
     public int startingHealth = 30;    
     public int currentHealth;         
     public int scoreValue = 10; 
 
     bool damaged;                                               // True when the player gets damaged.
     bool isDead;   
     Animator anim;    
 
     private float timer = 0;
     private float timerCooldown = 0.2f;
 
     void Awake ()
     {
         anim = GetComponent <Animator> ();
         bool isDead = false;
         currentHealth = startingHealth;
     }
 
     void Update ()
     {            
         timer += Time.deltaTime;
 
         if (damaged)
         {
             anim.SetBool ("isHit", true);
         //    timer = 0;
         }
 
         if (timer >= timerCooldown)
         {
             anim.SetBool ("isHit", false);
         }
     }
 
 
     public void TakeDamage (int amount)
     {
         damaged = true;
 
         currentHealth -= amount;
 
         if(currentHealth <= 0 && !isDead)
         {
             Death ();
         }
             
         timer = 0;
     }
 
     void Death ()
     {
         isDead = true;
         ScoreManager.score += scoreValue;
         Destroy(gameObject);
     }
 }

Any help on why I can only attack the original and not any instaniated (clone) prefabs of the same enemy.

I can have multiple prefabs hit me.. but I can't see to hit or dmg more than just the one original enemy.

Thanks alot guys.