What is the exact size when a Shrimp is called a Prawn instead of a shrimp. (buy count per pound)?

Shrimp and Prawns are 2 different creatures.

The Name "Prawn" has come to be a generic term used in some languages/regions to refer to shrimp.

The general lack of knowledge of the actual zoological distinctions between the 2 different animals,,,,,

AND their very similar appearance,,,,

has caused the term to become sorta "Generic-ized" to mean Large Shrimp.

Which makes it a "Fair Question" & Logical to ask questions such as yours,,ie:

"At what size do Shrimp become considered Prawns"

If the actual distinction between the 2 different animals is dismissed,,

And the Common & Accepted terminology is used....

There's still no "Rule" or Standard of Size distinction.

One seafood Merchant's Shrimp,,,might be another's "Prawns",,

and vice versa.

It's then down to whatever a person choses to call them.

Otherwise,,in reality,,,the Shrimp=Prawn=Shrimp thing is the same as ,,,

"How big do Blue Crabs or Fiddler Crabs,etc have to get to be called Alaskan King Crabs?.

Or,,"How Large of a Duck is called a Goose,,and then

how large of a Goose is called a Swan??"

Shrimp are "Pleocyemata"

Prawns are "Dendrobranchiata"

2 different animals

I call it both, I think shrimp are smaller than prawns. I live in New Zealand

Technically U-10's and larger are prawns, or anything with 10 or less per pound. That would make them at least 1.6 wOz. each. You will see it used out of place quite often though.

Shrimps and Prawns are the same thing, arent they? It just depends on what country you are from

U6 is a prawn

Shrimp has lobster kind of color whereas prawn has kind of dark brown color.