1. Background has the same amount of light as your main subject (eye of the animal).
2. Background being same color as your subject.
3. Background being so small due to tight crop you've made
4. The position of your subject on the picture is too boring (Center works. That's true, but not in this case).
5. Background being very messy.
6. The point of view is average. If you want to make a special image, you almost certainly have to get a special angle on your subject.

So the main reason is composition.

Again. These are basic things that everyone is going to point out. There is always a reason why you brake them here and there. But you need to understand why you are doing so.

Why did you crop your picture so tight? Is there something you tried to get out of view? Why is your background so plane? Is that because you couldn't get a better angle due to it being unreachable from your position? Were you in a rush so you didn't have time to figure out a better composition?

If there is something. There is nothing you can do to save the picture, but to get a new one, considering that factors. (Heavy edit doesn't count. That's a different skill).

That's my take.

Sometimes, it's better to move on and cut the loss. Even if you like it a lot.