There are many small fish in Duke Zhou's puddle. I put my foot in a puddle and the fish bit my foot.
Because "fish" and "surplus" are homophonic, in China's traditional view of dream interpretation, dreaming of fish has always been closely related to wealth.
Dreaming of fish swimming in clear water symbolizes that you will gain wealth and power, or that you are in a good mood and situation now, or that you will have unexpected income or status promotion.