How do I display related or similar Ads by currency on the Ad show page?

Hi Chris I need your help on this please.  I'm trying to display related Ads on the Ad show page by currency. But somehow  my script displays the same Ad in multiples of related Ads and not showing the actual related Ads. 

belongs_to :currency

has_many :ads

def show
@related_ads = Ad.where.not(currency_id: @ad.currency_id)

<% @related_ads.each do |ad| %>
<%= @ad.name %>
<% end %>

Thanks

Thanks a lot Jack! It should be 'ad' in the show page instead of '@ad' and ads_controller:
def show
@related_ads = Ad.where(currency_id: @ad.currency_id)
This works fine.