For starters from a technical standpoint your composition is near perfect and you’ve frozen the animal in time and isolated it from the background with great precision. You’ve simplified the photograph by using a limited assortment of colors and the shapes (i.e. triangles) that the profile view of the animal’s face and the antlers create is one of the most visually impressive shapes in photography according to the mathematics of art! So you’ve done a great job in those areas.
Most importantly, in this photograph you’ve kept the 4 walls of your photograph very “clean”. You’ve only included elements that would help better the image. There are no distracting, cut off (amputated parts) or pointless elements in this photograph.
Your second photograph is also very well done from a technical standpoint. It’s harder to capture than the first photograph because of the camera movement involved but your composition isn’t as strong in this photograph.
The mistakes are easy to fix and you’ll likely kick yourself for not noticing earlier but I’ll highlight a couple of the problems for you anyway. Even though you haven’t completed the lesson on frame organization and “amputation” yet, I’m going to point it out for you in this photograph anyway so you’re aware of it in the future.
The most distracting element in the fish picture is the frame composition. You’ve ‘cut off” or “amputated” the fish’s tail with the left wall of your photograph. This is the most common mistake that photographers make when before they take a course like this. It seems as though you were too focused on the main object and the center of your photograph and you ignored the 4 walls. Great photographs always have well composed centers and their edges are clean and clear of amputations.
But other than that… Both are great photographs! I look forward to seeing your next assignment.