i have 2 saves with different start. In the first one, i frequently go fishing until i unlocked carbon rod from day 40. in the other, i skip a portion of features to focus on story, and when i looked for a carbon rod on day 40, there was only normal rod. Fishing several times and i got reinforced, then fiber from near day 50. So i wonder what is the condition to unlock every rod tiers? Were they related to fish catched amount, money got from selling fish, or time from unlocked all fishing area?