I'd say yes, this is normal behavior for a fish that's not comfortable in it's environments, as it's instinctive. Lights on mean day time predators from above. Lights out means nocturnal predators from below. Make sure to provide lots of cover--gouramies like broad leaf plants to hide under, as well as build bubble nests to breed. Most will take a while to get comfortable, and even then, are seldom the most out going of fish. The more cover available, the most relaxed and outgoing the fish will be.