How to Reduce Reflection? (Glass-surfing)

I have a little betta fish who, admittedly, is rather new (1 week); so I've been told to expect him to glass surf a bit until he gets comfortable. He only flares every so often but seems to be very obviously chasing his reflection, and I'm really not sure how to help him out?

I've covered the sides with coloured construction paper for now (light pink, since I was told lighter colours will show the reflection less), and I can't particularly move the light as the small LED packet for the hood only has one place to properly attach. I've also tried to dull the light out a bit with some layers of tape and marker (colouring it and making it darker). I was thinking about painting the sides and back but seeing as the paper doesn't help too much I wasn't sure if even that would work :/ Any other suggestions, or should I just wait longer for him to get more comfortable?

Floating vegetation, like duckweed, or other LFS variety types may really help calm the betta. Most likely the fish has very little orientation, so floating plants will help and aerate the water as well (live plants).

It looks like this is a 5 gal aquarium, then using Dollarama construction paper (black) on the sides will help. I use black paper on three sides of my tanks (I use foam core board).