Fish Serving Set

I am pretty good at this but what do 3 forks mean?
Hi, help me here. So, you’re sitting on a dinner table and you have 3 forks.
Usually there are 2 forks.
1) Salad Fork.
2) Main course fork.
3) The top of the plate is for Dessert Spoon and fork.
What the heck is the 3rd fork for? Fish? And is it possible to set a Fish Fork and not serve fish?
Typically the third fork very delicate and is for fish or shellfish, and typically the flatware for dessert is above your plate.
HOWEVER, some people only put a dessert spoon above the plate and a Dessert Fork alongside the plate. It’s a confusing world out there, eh?
Just remember to move from outside in and you should be fine.