How?!
I don't consider allowing all the fish that don't use ladders to die anything but "terrible for fish."
Except it is only temporary, which means that the problem solves itself. Most fish are pretty proficient at ladders. It isn't like they are going to go extinct.EDIT: And most species of fish die when they go to spawn anyway, so it doesn't really kill anything.
Touchscreens that work decently
umthose already exist