Spear fishing?

Another great fishing option are the fishing traps (especially while living on Sulani), as once set they catch a few fish per trap overnight (plus treasure, at least on Sulani). They are portable, so you could also take them somewhere else and camp overnight. You do have to stay on the lot (no loading screens) though, else they unset. They seem to catch fish in the early morning, like when plants grow. If you have a stocked pond on your home lot (or a Park etc), you can also use them there.

You can also fish from the canoes on any body of water.