Here is a robot that helps you keep your aquarium clean. Robosnail is a fully automated glass cleaner that prevents algae build up on the aquariums surface. It can clean the surface of your aquarium once a day and works on standard glass aquariums of 55 gallons up to 150 gallon aquariums. The battery lasts 30 minutes.
Robosnail works on freestanding, rimless, and in wall mounted aquariums. It can detect edges and come up with the proper cleaning pattern on its own. Costs under $300 at this time.