Swarms of these newly freshwater fish migrate up streams and rivers, sometimes piling on top of each other to clear obstacles and predators.

这些新出现的淡水鱼群向溪流和河流上游迁徙，有时会在彼此身上堆积起来，以清除障碍物和捕食者。

Eyewitnesses described being trapped in a narrow, sloping alleyway, and scrambling to get out of the suffocating crowd as people piled on top of one another.

目击者描述说，他们被困在一条狭窄、倾斜的小巷里，当人们一个接一个地挤在一起时，他们争先恐后地从令人窒息的人群逃出来。