The concept isn't new. WDFW uses pumps to move fish in their hatcheries. My understanding is that the first ones were converted pumps used to move tomatoes in canning facilities without damaging/bruising/breaking them. It is not a big jump to move fish.

Did a Google search and found the following link to a Canadian company that builds pumps to move fish of all sizes.

http://inventivemarine.com/canavac/