Filming tiny animals in a drop of water

With a stereo microscope such as the Motic SMZ-171 and a camera such as the Moticam 1080, you can make excellent photos and videos of tiny aquatic animals swimming around in a small amount of water (sometimes in a single drop only) which is in a Petri dish or on an object-glass. The illumination of the object is essential here.

A Motic darkfield attachment and side lighting with two flexible optic fiber LED lamps were used for this video. The trick is to suppress the glare caused by the reflection of light from the water drop as much as possible. This was not entirely successful here, because indirect side-illumination was not used, whereby the light rays are first reflected on a white surface before hitting the object. An opal filter could also have been used.

The video starts with the title ‘Daphnia’. We are dealing here with the Simocephalus vetulus. This water flea has a relatively small head, clearly demarcated from the shield by a cavity on the dorsal side. The maximum height of the shield is behind the center. The green algae that we see are called Spirogyra, so named after the spiral arrangement of the chloroplasts.