Utrecht’s fish doorbell returns March 2 to help migrating fish

The world’s first Fish Doorbell at the Weerdsluis in Utrecht will resume operation on March 2, 2026, after taking a winter break. The interactive livestream allows viewers worldwide to help thousands of fish navigate the city’s canals during their spring migration.

Every year, fish swim through the Oudegracht and other Utrecht waterways searching for spawning grounds. The Weerdsluis, a manually operated lock, often remains closed, leaving fish stranded and vulnerable to predators. The Fish Doorbell allows viewers to alert a lock keeper to open the gates when fish appear on the underwater camera, helping them continue their journey.

The project is run by the municipality of Utrecht, Hoogheemraadschap De Stichtse Rijnlanden (HDSR), and Mark van Heukelum of Dutch Wallfish. It has drawn global attention: in 2024, 2.7 million viewers from countries including the United States and Brazil participated. In 2025, the site recorded 30 million visits from 2.3 million unique users, with over 200,000 doorbell rings reported.

In 2025, 13 species were observed, including eel, bleak, perch, pike, bream, and catfish. Rare species such as eel and bleak indicate good water quality. Data also showed fish were most active in the early morning, at dusk, and after dark.

The initiative has received international recognition. After British-American comedian John Oliver mentioned the project on Last Week Tonight, daily visitors to the site nearly quadrupled. Germany led global participation last year with 464,000 users, followed by the United States (137,000) and the Netherlands (131,000).

The Fish Doorbell operates annually from early March through late May, allowing viewers to ring the bell whenever they spot fish at the lock. The livestream and bell will be back on March 2, 2026.