The word freshwater is an adjective. Freshwater means (1) relating to or living in or consisting of water that is not salty.
The following articles and web pages elaborate on the word freshwater.
Freshwater Reels
Freshwater rivers and lakes are plentiful throughout America, and freshwater fishing is a hobby that is accessible to most people.
https://www.FishingReels.us/freshwater-reels.htm
About Fishing
This helpful page details the sport of fishing and includes a history and description of a much favored pastime. Helpful resources are included.
https://www.Fishing-Tackle.us/fishing.htm
Saltwater Reels
Saltwater fishing differs from freshwater fishing, and it requires a different type of rod, reel, and accessories. Links to saltwater fishing reel suppliers are included on the page.
Lake Tahoe is a freshwater lake that is located in the Sierra Nevada region of the United States on the border of California and Nevada. It is the largest alpine lake in North America, attracting about three million people to its shoreline each year.
https://en.wikipedia.org/wiki/lake_tahoe
The following digital image illustrates the word freshwater.