Police in Hannover said several freshwater crabs escaped when their container overturned during the journey on the high speed ICE service at Göttingen and made their way through the carriages.
The crabs were recaptured one by one but not all of them returned to their container.
“Some of the animals were not found,” a police spokesman said.
The crabs where handed over to the fire service’s animal rescue department in Göttingen while the two passengers who brought the crabs onto the train had to pay for the costs.
Authorities also checked to see if the crabs were protected.
Freshwater crabs are a Chinese delicacy.