Forget fish ladder, they’re building a whole river! Lol
Basically The Netherlands built the Afsluitdijk dam to protect against flooding from the North Sea, but it blocks off the migratory path for fish seeking freshwater to breed. The Fish Migration River is being built to correct that. It’s projected to be completed by the end of 2026 and will be both a nature reserve and UNESCO site.
More reading: https://www.holland.com/global/press/news-resources/fish-migration-flow-at-the-afsluitdijk
2 min video animation for how it works: https://youtu.be/rduAVvQY0lE
I’ve only seen those used for salmon because those are large fish that make a concentrated seasonal migration in from the ocean. Fish ladders are fine for other species that are smaller and inhabit the river year round.