It seems the same type of fish can very different charateristics, my brothers BN is only ever out after lights out, same with his clown.
I suppose it has a lot to do with the individual tank and other fish they live with.
My bulldog could be eating at night, but im pretty sure it doesnt, my loaches tend to finish anything off thats on the bottom. I think my pleco liveson algae, i do have a lot of it at the moment!