More than a year: the pronunciation of "fish" and "jade" is similar, and people want it for more than a year, so jade fish can take the meaning of "more than a year".
Harmonious life: Small fish living in water are carefree and rarely encounter obstacles and bumps. When people describe someone's life and career as smooth sailing, they will say that this person lives like a duck to water.
Many children are blessed: mother fish has many fish eggs in her stomach. Therefore, jade fish symbolizes many children and many blessings.