This may be a new twist on whether fish actually recognize us or something we are holding.
I have a bank of tanks outside with another tank that is perpendicular to the bank of tanks. Today, I was holding a can of food as well as a breeding slate for the back tank as I went behind the bank of tanks. Normally, when I open the back door to the porch where the fish are, they all come running to that side of the tank. I thought it was me they were coming for. lol Today, I went behind the tanks and put down the can of food so I had 2 hands to deal with placing the breeding slate in the one tank. I noticed that the fish were not looking at me but out the side glass instead. I couldn't believe my eyes. So I went in and got my camera and repeated what I had just done. Keep in mind that I am standing directly behind the tank. Only the camera is at an angle to avoid flashback. In pic #1, you'll notice that the fish in the back are not looking out the back glass where I am standing but are looking out the side. The larger fish in the front just moved from the side view as I snapped the picture. In pic #2, you'll see what they were looking at. Most of the fish were still looking at the "prize" when I snapped the pic. So is it really me they recognize?