Fish in the Gamecube version then play the ones after(DS and Wii), it's pretty apparent that fishing was nerfed to tone down the money you could make in it. Back on the Gamecube it was pretty easy to do good fishing, especially on a rainy morning. Now if you're lucky on a rainy morning you'll pull in 50k or so, and that's IF you're lucky. Sea basses are not only way more common but also look like large fish now. Your fishing line now moves towards the shore rather than outwards like in the Gamecube version, making it much harder to attract the attention of fish. In the Wii version if you attract a fish it also has a chance of "teasing" the line where it nibbles and runs off, which is a slap in the face after spending a few minutes trying to get the bobber in the right spot.

It's all just a way more painful experience to try to push the other forms of money-making on the players even though they still suck. I hardly fished in the Wii version at all, even on rainy days. It's just that bad.