The ornamental fish were found in a plastic bag placed in a trash container on the Wurmbülstrasse, Winterthur city police said in a news release issued on Monday.
The discovery was made on Saturday when many of the fish were already dead, police from the city in the canton of Zurich said.
Officers brought the surviving fish to a pet shop where efforts were under way to save them.
The owner of the fish, tracked down, said he become tired of the fish because of the apartment move, police said.
Switzerland has some of the tightest animal welfare legislation in the world, regulating the way humans behave towards animals.
The principle of the law is that pain, damage or suffering “must not be unjustifiably inflicted on an animal, nor must any animal be subjected to severe anxiety”, according to information from the federal food safety and veterinary office.
“The neglect, overexertion or mishandling of animals if forbidden.”