Accidentally selected option "Laugh in his face" in the quest 'Go Fish' to the fisherman.

Any way to fix the problem?

I believe you can use a Charm spell on him to bring his disposition back up to 20. Or you can load a previous save.

He really gets offended when you laugh in his face.

According to the wiki that lowers his disposition by 60, and you need to get up up to above 20 to get the quest. As Pseron Wyrd says, charm should work (confirmed by the wiki).