“Journey to the Microcosmos: Water Fleas: Look Weird, Adapt Weirder” explores water fleas, or cladocerans, with a focus on daphnia and their remarkable biological adaptations. The video explains crustacean anatomy, compound eyes, antennae, filter feeding, heart rate, hemoglobin-based oxygen transport, predator avoidance, diel vertical migration, kairomones, and defensive traits such as neck teeth. It also examines reproduction through parthenogenesis, cyclic parthenogenesis, environmentally influenced sex determination, and resting eggs. Using microscopy and life science vocabulary, this documentary connects organism structure, behavior, ecology, heredity, and survival in changing environments. The content strongly supports biology and environmental science topics commonly addressed in upper elementary through middle school curricula. Part of the "Journey to the Microcosmos" series.