Some aquarium hobbyists choose to culture copepods to supplement there reef and fish only aquariums. Copepods are easy to grow if you have a clean sterile environment and don’t over feed them. Really you are growing a microbial film on which they feed.
Other aquarists grow copepods to help feed there fish larvae. Aquaculture is a fast growing part of the hobby and benthic copepods can help keep tanks clean while feeding your fish.