Объекты спавнятся очень быстро. Как привязать к этому или другому алгоритму переменную от времени?

using System.Collections;
using UnityEditor.UIElements;
using UnityEngine;

public class SpawnZone : MonoBehaviour
{
    public Transform spawnZone;
    
    public Rigidbody fish;
    float maxX;
    float minX;
    float maxY;
    float minY;
   
    void Start()
    {
        minX = spawnZone.position.x + spawnZone.localScale.x / 2;
        maxX = spawnZone.position.x - spawnZone.localScale.x / 2;

        maxY = spawnZone.position.y + spawnZone.localScale.y / 2;
        minY = spawnZone.position.y - spawnZone.localScale.y / 2;
    }

    void Update() 
    {
        if (Input.GetKeyDown(KeyCode.F))
        {
            Vector3 spawnPos = new Vector3(Random.Range(minX, maxX), (Random.Range(minY, maxY)));
            Instantiate(fish, spawnPos, Quaternion.identity);
        }
        else
        {
            Vector3 spawnPos = new Vector3(Random.Range(minX, maxX), (Random.Range(minY, maxY)));
            Instantiate(fish, spawnPos, Quaternion.identity);
        }
    }
}