I have a couple suggestions:
1.Make a stone tier, it would fit better in the game.( it would be between wood and iron and could be called "Reinforced ____")
2.A netherack tier, it would be the same as the stone but would have a chance to cook your fish.
3.A "Treasure Rod", made with gold, diamonds, and emeralds.(It would have a chance to get treasure, like iron, gold, diamonds, emeralds, armor, etc.)
Woah, im really loving this mod, the minecraft community really needs more fishing mods, I cant help but think about this mod in-joint with the fish and farm mod, you've done an excellent job, keep up the good work!
Now if it added a bit like Mo Creatures, where you could see some fish swimming around, and technically get those. But still get a chance of getting better fish you don't see. Maybe also add a spear, so it's cheaper and slower than a harpoon, but probably more fun if the fish are visible.
nice mod! i was planning on adding something like this to the fantastic fish mod( currently WIP) eventually. what do you think about combining the mods and joining up with the team? if you have no interest whatsoever at least consider working with us to make the mods "compatible" so that player can catch our fish with your rods.