The fresh water crayfish
In addition to fish, it is above all invertebrate aquatic organisms that turn the Senne streams into species-rich habitats. The amphipods are among the most common small animals. The best known representative is the fresh water crayfish. It has a brownish armour colour and grows up to 2 cm in size. It feeds mainly on dead plant material such as leaves, which it filters out of the water.
Since the fresh water crayfish is widespread and numerous in small rivers, it is an important food source, especially for fish. Good occurrences are particularly found in clean and naturally structured waters. It finds these good living conditions above all in the upper reaches of the Senne streams.