Erwachsene Fischegel: Befall eines Fisches (Bitterling). Jungegel: Befall und Verlassen einer Kaulquappe, Massenbefall eines Fisches.

The searching movements of the fish leech Piscicola geometra as well as its mode of transfer to the fish is demonstrated in the first scenes of the film. The following frames show the behaviour on the host and once again the sequence of attachment of a leech to the fish. Juvenile leeches lurk in a same manner for their hosts. After attaching to a tadpole they quickly leave; in contrast on a fish they suck blood.