We did the Bass excursion at Caribbean Beach, which left from the marina by the main pool. We booked in advance.
It was all catch and release with live bait, all large mouth bass. The bass are very well trained, Disney style, and will jump on your hook regularly. The host was great, and knew where all the best spots were. He would set multiple rods for my son. The boat was very comfortable.
They provided bottled water as I recall, maybe pop. All in all, expensive but a good memory.
We also tried fishing at Riverside and caught one tiny fish. It's very controlled - very small body of water cut off from the main river, set hours and you can't access outside those hours.
I'm not clear on Disney policy on people just fishing off the banks at any of the lakeside resorts. I've seen people doing it, but have heard that they'll intercept you on the safety factor (gators). More likely it's the economic factor - ie, it's free.