I think you should try interacting with him more often. My FH was having a similar issue of hiding when I first got him. So, I read some stuff on flowerhorncraze.com about helping to get them used to you. When you clean, have your hands in there for longer, spend time next to the tank, try running your finger on the glass to interact, always walk up slowly at first, etc.
When feeding, I place the container up against the glass for a minute before I put the pellets in. I leave my hand rested on top. You can also try signalling by splashing the water with one finger before feeding. This not only trains them and allows you to see their hunger-schedule, but gets them used to your presence.
Oscars have a similar intelligence and social interaction to FHs, so I would guess that this would work also for yours. The light-thing, I'm not sure. But, you can always try these things. When you have a fish that is going to get big and aggressive, it is safest for you and the fish to have a comfort level and some minor training. Makes for a happier fish<3