"The fire at the city gate will harm the fish in the pool" comes from Du Bi's Baliangwen in the Northern Qi Dynasty: "I am afraid that the Chu ape will die, delay the trees, and the fire at the city gate will harm the fish in the pool." Its meaning can be explained as follows:
Once upon a time, there was a place where there was a pond under the city gate and a group of fish swam happily in it. Suddenly, the gate was on fire. A fish saw it and shouted, "No, the gate is on fire. Run!" " "But other fish don't think so. They think there is a fire at the city gate, which is far from the pond, so there is no need to make a fuss.
Except that fish escaped (regardless of its escape mode for the time being), none of the other fish escaped.
At this time, people came to the pond to get water and put out the fire with water. After a while, the fire was put out, the water in the pond was drained, and the fish in the pond were damaged.
This story tells us that there is a connection between fire, water and fish. The water in the pond can put out the fire in the city gate, which is a direct connection, while the fish is indirectly connected with the fire in the city gate, which is connected through the intermediate link of pool water. Metaphor is suffering for no reason.