Off to a good start with a very capable camera! That hawk of yours is checking you out, I think he wants food
I don't want to dampen your enthusiasm, but if you don't mind a little critique, read on:
Your idea behind this pose is great, because it demonstrates the personality of the fish, and there is interaction between the fish and the viewer. Technically speaking, the eye(s) of the fish should be in sharp focus, because we communicate by looking at eyes.
Compositionally, this photo would be improved if the fish is less centered. I would like to see the fish more to the bottom left. Why? Since the fish is looking to the right, give him more negative space so it looks like he could swim into that space. In addition, this serves to crop out the out-of-focus (OOF)
C. racemosa to the left. The green of the macro algae compliments the red of the fish, but it is a little distracting having that much of it, especially the ones at center left.
Anyhow, love to see more!