How I would put a rod in, I would take the character walking png and edit it with a fishing pole name it fishing png and then use it in the event with either change picture in the moving event or in the event pages. I think though, you could find fishing sprites on
http://forums.rpgmakerweb.com I am pretty sure I saw some free to use on that site although it might have been for npcs. (also, you could take the battler png and use the sword swing and just edit in the pole) there is a free to use pyxel edit program that is pretty simple and could make it easy if you have never done anything like that before.