Why you are not allowed to release animals into our pond

The pond on our institute’s  premises is part of the BioDiversum, a newly created biotope designed to provide a habitat for endangered animal and plant species. To create a stable ecosystem it is important that the pond’s flora and fauna can develop naturally. Apart from a few native aquatic plants in the beginning, we do not introduce any animals or plants into the pond ourselves. Therefore, please refrain from releasing fish, turtles, or other animals as well!

The release of non-native fish, turtles, and other animals into the wild is prohibited by law and may be fined!

Why are introduced fish a problem?

Introduced fish can destroy the pond’s ecosystem within a very short time. They displace native species and often reproduce to such an extent that the water loses its ecological balance.

Some fish species that are popular for garden ponds, such as bluegills, are extremely aggressive. They can bite native fish, such as tench and carp, injuring them so severely that their populations decline rapidly.

Sunfish harm native fish populations because they eat their spawn and offspring.

The popular garden pond goldfish are an even bigger problem in natural waters. Among other things, they eat the spawn and tadpoles of frogs and other amphibians, thereby endangering their populations. Their prey also includes water fleas, which constantly filter and thus clean the pond water. In addition, goldfish reproduce so quickly that they displace other fish in the medium term. Therefore, goldfish in a pond are an ecological disaster.

What about turtles?

Turtles such as the red-eared slider turtle also threaten the pond’s ecosystem. They are omnivores and feed on the eggs and larvae of various aquatic animals. In addition, like goldfish, they eat microorganisms that clean the water. Some plants are also on their menu. Exotic turtles thus threaten the biodiversity in the pond. In particular, rare species such as the great crested newt and the tree frog suffer.