If someone made $5K for an article in any mainstream publication -- outside of an exhaustive feature like you find in monthly magazines -- I would buy them champagne to celebrate. And those $5K pieces go to established and well known writers.
I made a "living" as a freelance writer for several years writing for newspapers and magazines and I can tell you a few things:
Get ready to hustle. If you're an unknown you will be writing articles on spec, which is essentially writing something on your own and submitting it for consideration blind. Most outlets do not accept on spec articles and you'll have to blanket the industry to get a few nibbles. For those who do not accept on spec, prepare to email or call every editor you can reach to propose article ideas. Prepare for rejection.
Most publications pay anywhere from $50 to $500 for regular articles. Sounds decent at the upper range but you aren't selling articles every day...or even every week. Freelance writing generally pays worse than staff writing gigs. Writing about fishing may combine your love of fishing and writing, but remember you won't be eating well. Prepare for rejection.
I made okay money as an occasional contributing editor but most of my writing was on spec. I approached dozens to over one hundred outlets with on spec work or ideas. The fishing news world has a lot fewer options. You will have a difficult time making a living unless you land a full-time gig (and remember, the average journalist pulls in about $35,000 a year, hardly princely wages). Prepare for rejection.
Have I mentioned you should be prepared for rejection?
My opinion and worth what you paid for it. I'm not trying to dissuade you from going down this route -- money isn't everything but it's a hard row to hoe. Might not be a bad idea to offer your services for free to a few publications writing some minor stuff to help them and seeing if you can build a relationship that will lead to bigger things.
Good luck, I do wish you well.