Is the red fish (carp) the Lijiang symbol? Why?

As far as I know, I only know the fish means abundance, but I did not hear about the saying " The red fish is the symbol of LJ".
In Chinese culture, there is a old saying called Niannian Youyu (The fish will be left every year). If the fish was left, it means the food was rich and can be in surplus. This sentences has a auspicious meaning and it is the representative of the people new hope for the next year. But why they say the red fish is the symbol of that old town, I am not afraid that I am not very clear.