Ahlhorner Fischteiche, Nature reserve in Grossenkneten and Emstek, Germany

Ahlhorner Fischteiche is a nature reserve in the municipalities of Grossenkneten and Emstek, made up of a large number of fish ponds, wet meadows, and wooded edges along the water. The ponds vary in size and depth, and the land between them shifts between open grassland, reed beds, and patches of trees.

The first pond, the Rüdersee, was dug in 1884 in a spring-fed hollow. In 1898 the fish-farming inspector Riggert surveyed the Grand Duchy of Oldenburg and chose Ahlhorn; the Landeskulturfonds then bought the heathland. Carp ponds were begun by 1901 on the Katzenkopf plot, and between 1906 and 1929 Julius Keimer directed the layout, reaching 54 ponds covering 200.5 hectares.

The ponds belong to the Niedersächsische Landesforsten, making them the only publicly owned fish farm in Lower Saxony. Carp have been raised here since the first pond, the Rüdersee, was dug in 1884, and the state pond farm was developed from 1901 on the Katzenkopf plot. Today management follows the LÖWE program adopted by the state parliament in 1991.

The reserve can be entered from several points, and marked footpaths lead along the ponds and through the wetland areas. Waterproof shoes are a good idea, as sections of the trails can be muddy, especially after rain.

The reserve is the only fish-breeding facility in Lower Saxony in public ownership, managed by the Niedersächsische Landesforsten. Since 1998 the 19-hectare Ahlhorn natural forest has accompanied the Lethe as the only purely streamside area in the state's natural forest programme.