What's so important about eating fish?

This fish-eating (or rather the recording of it) is meant to show that Jesus is not an apparition. He's not a ghost. He is real. He has a real body. Thomas can touch his hands and side. Jesus can eat fish. Jesus' resurrection, God's promises, heaven's hope, and our future joy in the life of the world to come is as real as the fish the disciples caught and Jesus enjoyed with them that day.