Can pin-fish come in fresh water?

The term "pin-fish" is not a recognized scientific classification. It's likely a colloquial term, and it's impossible to say for sure what fish you are referring to without more information.

Here's why:

* "Pin-fish" could refer to a variety of small fish: There are many small fish species, some of which might be called "pin-fish" in a specific region.

* Freshwater vs. saltwater: Fish species are either adapted to freshwater or saltwater environments.

To help me understand, please tell me:

* Where did you hear the term "pin-fish"?

* Can you describe the fish you are asking about? (Size, color, shape, location where you saw it)

Once I have more information, I can help you determine if it's a freshwater or saltwater fish.