Harvest moon magical melody ?

i need some help im doing fine on it but ..... i dont know what the heck a turffle is..... all i can find on the internet is "you must have a pig to find truffles !" or something like that ! and also if you have a tip to get to the bottom of the cave thing where i find a lake to ketch that squid thing i would really like that because i keep going to level 10 and i keep having to go back to the top and start over .... oh and one other thing lol how can i make the dolphen like me faster ... dose it like ANY kinda fish orrrrr what ? i really need some help !