Customs officials in Germany have found 26,000 fish inside thousands of sealed glass vases hidden in the back of a truck.
According to the news agency Reuters, the White cloud mountain minnows, Tanichthys albonubes, were in pairs inside sealed vases containing a plastic flower and had no access to clean water or oxygen.
Hartmut Steinen, spokesman for the Authority for Science and Health in Hamburg told Reuters: "I have never seen such a case like this before.
"I don't know why someone would transport so many fish in such terrible conditions that flout every animal welfare regulation."
The lorry was reportedly on its way to Hungary from a Chinese company.
The fish have since been rescued by the Hamburg Zoological Institute.