May seem a little far fetched, but I’ve spent a lot of time interacting with different animals, fish included. They are a lot smarter than some could imagine. If you give them FaceTime, just like you would your pet dog or cat, they will react to it. Yes, I talk to my fish. The main thing they react to is “are you guys hungry?” When I say that, they will all come out and swim to the feeding location. Repetition is the key to get them to connect the sounds to the action. Just like saying walkie to your dog. They know what it means because they can match up the particular sounds to the event. Same as when you put your pumps in feed mode. They know (assume) it’s feeding time.