You just have to ask the right question all the times.
Yes, I have 4 in my pond creating a clockwise current which could be turned into counterclockwise every month.
Not only it creates current for the fish to exercise, it helps keeping the bottom of the pond cleaner.
compared to wall jet, mixing eductor creates much more current. 1 gallon -> 5 gallons from the nozzle. Pretty amazing stuff.
Downside:
1. something sticks out inside the pond, your fish can hurt themselves if they are crazy. Mine haven't had anything happen yet.
2. It will take some pump power to create adequate current at 3' depth. But again, anything for our koi right?