Go to Guang Ling [ upper right above jianye ]
the shopkeeper there selling : insect bait, fish bait and ultimate bait

if u want to farm Yibiqian
buy the fish bait dont buy ultimate bait
and go to the port below guangling
just fish there.

randomly get golden yibiqian ^^
1 gold = 4 yibiqian
if lucky gan get up to 6 gold yibiqian ^^

have fun farming