Gu also had a sideline in Ganquan village, which was to help the old fishermen make a fish dish. How? Where can I buy fish?

After entering Ganquan village, talk to Zen Lao.

Fish head pot (Jiangdu's recipe) can be made by cooking system.

If there is a fish head pot in the item

Talk to it again to complete the task.

You can eat fish in Taohuagu pond.

You don't have to go to Peach Blossom Valley now.

As long as you accept the task

You can wait until the plot of the first imperial tomb is over, and then come back with fish.

Grandpa will wait for you. ...