Humans. What other sentient being designs a tool requiring hands and feet and expects animals without limbs to use it? Alas, the answer is humans.
Humans created a ladder for fish, which is quite effective in certain situations – but isn’t a blanket solution to every fish passage problem.
And while most humans would agree that ladders can be useful for climbing short distances, perhaps 20-50 feet– another tool – like an elevator or truck – may be a better option to climb hundreds of feet. Otherwise, there would need to be more infrastructure to support that ladder, or perhaps it would need to be a staircase at that point.
This is similar for fish when moving them up and downstream.