1. What makes it an effective image?
I like the color and composition and the eye contact.
2. How was the photo/subject it lit?
Tank lighting only
3. Does the image capture the personality or essence of the subject?
IMO Absolutely! He looks curious to me.
4. Is there any question about what the main subject of the photo is?
I don't think so.
5. Is there anything that the Photographer could have been done technically to make this a better
photo?
I would like to have seen a tiny bit more DOF and maybe a bit more post sharpening. I like to see detail in the focus area.