Eheim GmbH & Co. KG is a German company founded by Gunther Eheim, operating in the domain of aquarium

Aquarium

An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

s and aquarium accessories. It manufactures different kinds of water filters (internal and external) and the associated filter media, pump

Pump

A pump is a device used to move fluids, such as liquids, gases or slurries.A pump displaces a volume by physical or mechanical action. Pumps fall into three major groups: direct lift, displacement, and gravity pumps...

s, accessories such as aquarium fish feeder

Aquarium fish feeder

Aquarium fish feeders are electric or electronic devices that are designed to feed aquarium fish at regular intervals. They are often used to feed fish when the aquarist is on vacation or is too busy to maintain a regular feeding schedule.-Design:...

s, gravel cleaners and garden ponds, while its subsidiaries MP (Mueller and Pfleger) manufacture aquariums and Jäger, aquarium heaters.

Also, a modern and seemingly unrelated domain that Eheim got indirectly involved in is the use of its aquarium pumps in the liquid-cooling systems of overclocked

Overclocking

Overclocking is the process of operating a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, but some manufacturers purposely underclock their components to improve battery life. Many people just overclock or 'rightclock' their hardware to...

computers. Similarly to aquarium filters, these cooling systems require small water pumps with a low noise level and reliable continuous operation.