Hairgrass grows best in good light. It does look like a thin bladed grass, but without lots of trimming it tends to grow up to and across the top of the tank. I've heard there is a low growing variety but I haven't seen it yet.
This is another good plant for fish fry to hide in. I like this one with anabantoids and livebearers. Though I did once have a halfbeak fry that once kept trying to impale himself through the gill with a blade of the hair grass. I finally had to remove the fish to a different tank.