C# error help ( CS0023 Operator '--' cannot be applied to operand of type 'Stat'

Ive been using the help of multiple sources for my code to pile together a game, and its working somewhat well except for the fact that i cant get my player to take damage

public class PlayerHealth : MonoBehaviour
{
    [SerializeField]
    private Stat health;

	private void Awake ()
    {
        health.Initialize();     
	}

	void Update ()
    {
        
    }
    void OnCollisionEnter2D(Collision2D coll)
    {
        if (coll.gameObject.tag == "blob_enemy")
        {
            health--;

            if (health < 0)
                health = 0;

            coll.gameObject.GetComponent<PlayerHealth>().receiveDamage(10);
        }
    }
    public void receiveDamage(float amount)
    {
        health -= amount;
        if (health <= 0)
        {
            Destroy(gameObject);
        }
    }
}

i don’t quite know what to do in this situation so some help would be appreciated, i’m using unity 5.6.

It looks like Stat has the -= operator overloaded so you could instead just say health-=1 instead of health–. Or you could go overload the – operator in the Stat class. C# operator overloading