+1 to the above comment. I do exactly that with my predator tank. That light specifically is only meant to be hung from the ceiling. It would require some thin cable and some screws and anchors from your local hardware store. You could make a DIY bracket if you really wanted too, but hanging would be much easier based upon your pictures.
What the others said, that is meant to be hung from the ceiling or a hood using those 4 holes for hooks or cables to thread through. Also, probably want to save the "emergency" tag for emergencies.