Abstract: Untethered robots utilizing environmental energy for aquatic information perception are significant for human–robot–environment interactions, which require strategies to reconcile self-powered locomotion and autonomous sensation. Inspired by rove beetles with Marangoni propulsion, we developed a self-propelled nanocellulose aerogel eco-robot with a parallelly patterned electrode array with equal gaps, demonstrating continuous locomotion on water and simultaneous electricity generation via an unreported continuous solid–liquid sliding contact electrification mechanism with sufficient charge transfer. Systematically studying the charge transfer mechanism between the locomotive robot and water surface at different robot geometry, motion status, and diversified water contamination conditions, the self-powered robot achieves locomotion status self-monitoring and water contaminant concentration detection with a high sensitivity of 99.6%. It also demonstrates water–organism interaction including fish motion perception and monitoring. This work proposes a concept for constructing a smart aquatic ecosystem utilizing robots with self-powered mechanical–electrical cooperativity, demonstrating autonomous environmental energy utilization for information acquisition and interaction.