You can't miss the small fish. There is always only one fish that is smaller than you and when you eat it a new one will spawn. All other fish are bigger than what you will be and also bigger than what you will become if you eat the small fish. I may add some additional visual cues for the fish that are bigger but I actually loved this about the OG because there you also didn't know exactly when you are big enough to eat the bigger fish.
Yeah I saw about the spawning on the edge I will take that into account.