In Indonesia this plant is known by the name of a waterwheel plant. This plant is growing very fast, up to 4-9 mm per day.
Aldrovanda vesicula is dominated by 6-11 cm stems floating above the water. This waterwheel plant has no roots like any other plant.
The inner plant trap consists of two open lobes, similar to the traps in the venus flytrap plant. The difference is the trappings of the mill are smaller and are in the water.
 
As small invertebrates enter the gap between the two lobes, it is almost certainly not safe. Because the vesicular trap aldrovanda only takes 10 milliseconds to close.
Nothing wrong if this water mill is crowned as an insectivorous plant that has the fastest movement in the world.