water quality wise, yes you can, as long as your filter is a good size (bichirs are messy) and you keep up with water changes (50% weekly is my minimum)
space/size-wise, up to you. They have the potential to grow up to 24" and a 24" wide tank would be my minimum, but you could get away with it. I've seen a 39" congicus in a 24" wide 180g looking happy.
What's your setup like? (filtration and decor)