What’s the best way to observe C-Fern sperm?

C-Fern sperm can be seen at magnifications as low as 20X. The critical factor is light from below and proper adjustment of the light source. If all else fails, try placing a piece of aluminum foil with a pencil lead-sized hole in it under the Petri dish culture or slide. View sperm swimming in the outside perimeter of the light coming through the hole.