.find(params[:id])が取得できません

前提・実現したいこと

find(params[:id])でidを取得して詳細表示させたい

発生している問題・エラーメッセージ

(prototypes_controller.rb)
ActiveRecord::RecordNotFound in PrototypesController#index
Couldn't find Prototype without an ID

 def show
    # binding.pry
    @prototype = Prototype.find(params[:id])ここでエラーになります
  end

該当のソースコード

prototypes_controller.rb

class PrototypesController < ApplicationController
  before_action :show

  def index
    @prototypes = Prototype.all
      # binding.pry
  end

  def new
    @prototype = Prototype.new
  end

  def create
    @prototype = Prototype.new(prototype_params) 
    # binding.pry
    if @prototype.save
      redirect_to root_path
    else
      render :new
    end
  end

  def show
    # binding.pry
    @prototype = Prototype.find(params[:id])
  end

  private
  def prototype_params
    params.require(:prototype).permit(:title,:catch_copy,:concept,:image)
    .merge(user_id: current_user.id)
  end

 
end

index.html.rb
<main class="main">
  <div class="inner">
    
    <% if user_signed_in? %>
      <div class="greeting"> 
        <%= "こんにちは" %>
        <%= link_to "#{current_user.name}さん", root_path, class: :greeting__link%>
      </div>
    <% else %>
   
      <div class="card__wrapper">
    <% end %>
     
      <%= render partial: "prototype", collection: @prototypes %>
    </div>
  </div>
</main>

_prototype.html.rb
<div class="card">
  <%= link_to image_tag(prototype.image, class: :card__img) , prototype_path(prototype.id) %>
  <div class="card__body">
    <%= link_to prototype.title,  prototype_path(prototype.id), class: :card__title%>
    <p class="card__summary">
      <%= prototype.catch_copy %>
    </p>
    <%= link_to "by #{prototype.user.name}", root_path, class: :card__user %>
  </div>
</div>

prototype.rb
class Prototype < ApplicationRecord
  belongs_to :user
  
  has_one_attached :image

  validates :title,      presence: true
  validates :catch_copy, presence: true
  validates :concept,    presence: true
  validates :image,      presence: true
end

user.rb
class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable

  has_many :prototypes

  validates :name, presence: true
  validates :profile, presence: true
  validates :occupation, presence: true
  validates :position, presence: true
end

routes.rb
Rails.application.routes.draw do
  devise_for :users
  get 'prototypes/index'
 

  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
  root to: "prototypes#index"
  resources :prototypes, only: [:index,:new,:create,:show]
 
end