My Interpretation :

The fish on the bottom left is looking at the other fishes which seem to be going nowhere, and the humans are walking around with no fixed aim. It is observing the entire scene or maybe trying to comprehend. The fish is scared a little bit. It sees a connection between the humans and the fishes. Even though there is knowledge and learning in their way, people choose not to see it . This might also signify ignorance to some extent. Also, all of us are constantly moving each day, but at the end where "are" we going? The fish is making this connection ( purpose) between them and the humans.