Dwarf Gourami not eating

Hi,

I have a 10-gallon aquarium, fully cycled via fishless
cycling, ammonia = 0, nitrites = 0, nitrates = 20 ppm,
pH = 7.2, some live and artificial plants, a big rock
with holes, and a ceramic piece with holes. Last week,
I added the first fish: 5 Neon Tetras, 2 Cory Cats, and
a Dwarf Gourami.

My concern is that the Dwarf Gourami is not eating. He
swims energetically at the back wall behind the plants
and rock/ceramic pieces all day including at feeding
time. He eats nothing or very little compared to the
Tetras. He's about two inches in length. The food is a
balanced flake.

Should I be worried? Should I try live food? Should I
turn off the room lights at night while feeding?

Thanks,
Kevin