Millions tune in as Utrecht’s fish doorbell goes live for fifth year

The world's only fish doorbell is live once again, allowing people worldwide to help migrating fish pass through the Weerdsluis lock in Utrecht. For the fifth consecutive year, the underwater livestream at visdeurbel.nl is open to viewers who can notify the lock keeper when fish are waiting to swim upstream.

Last year, more than 20 million people tuned in to watch, and over 150,000 times, viewers pressed the virtual doorbell to alert authorities to open the lock, according to Hoogheemraadschap De Stichtse Rijnlanden.

The Weerdsluis is a vital passage for fish migrating through Utrecht. "It is actually the only way fish can reach other waters," said city ecologist Anne Nijs. However, during the early spring, the lock remains mostly closed for boats, leaving fish stranded for weeks. "Then they can be eaten by other fish and birds," Nijs explained.

The fish doorbell was introduced to solve this problem. When a viewer sees a fish waiting, they can ring the digital doorbell, signaling the lock keeper to open the gate. Each year, thousands of fish are able to pass through because of the initiative.

While the project started as a local initiative, it has gained international attention. People from around the world participate, sharing their experiences on social media platforms like TikTok and X.

"We even receive fan mail," Nijs said. "This morning, someone asked when exactly the doorbell would go live because they wanted to throw a party for the occasion. We also hear from people who say watching the fish has helped them through difficult times, bringing them a sense of calm."

The fish doorbell is typically active from early March to late May. However, due to its popularity, last year the system remained operational for an extra month.

In previous years, measures have been taken to improve fish safety. Last year, structures were placed in the water to provide shelter from predators. This year, Utrecht introduced a new city mascot near the fish doorbell: Barry de Baars, named after the Dutch word for the European perch.

Data from last year showed that fish were most frequently seen in the early morning, at dusk, and shortly after dark. Certain species, like eels and pikeperch, were primarily spotted at night. Perch and bream were the most common, but viewers also saw northern pike, common rudd, and catfish.

The project’s global reach continues to expand. Last year, Utrecht reported that Germany had the most users (464,000), followed by the United States (137,000) and the Netherlands (131,000). Visitors from the United Kingdom, Austria, Switzerland, and Canada also participated.

Utrecht city alderman Linda Voortman emphasized the initiative’s importance. "The fish doorbell is embraced en masse every year by Utrecht residents and people far beyond. Last year, there was also a lot of international attention. This shows how many people enjoy the fish doorbell, but also how important it is. It is a wonderful initiative to increase knowledge about underwater nature."