Brine Shrimp

Live aquarium food is making a big comeback. From phytoplankton and bacterioplankton to copepods and amphipods, aquarists are rediscovering the benefits of using live feed. Because live feed seems so much more advanced than “prepared” alternatives, one might be surprised to learn that live fish food was the only fish food at one time; it may be hard to believe, but aquarium flake foods weren’t invented until the 1950s! So, what did aquarists use? Basically anything they could culture themselves (e.g. infusoria)! But, increasingly since the 1930s, brine shrimp (Artemia sp.) were a sure favorite. Brine shrimp remain important to the aquarium and aquaculture industries to this very day. This is partly due to their acceptability to fish and other aquatic animals, as they are quite enticing (especially the way they swim), palatable and nutritious. They are in large part favored by aquarists because they are easy to store for extended periods of time as dry cysts. This branchiopod crustacean lives in salt lakes rather than marine habitats. It certainly is well-named, as it can survive in waters more than twice as salty than seawater. During droughts, it forms dormant cysts. These cysts remain viable for years if kept cool, dry, cool and shielded from ultraviolet radiation. As non-selective filter-feeders, brine shrimp continuously sift particles like bacteria, phytoplankton and detritus from the water and pass them to their mouths with feather-like appendages on their legs. When the physical/chemical environment is comfy, brine shrimp produce free-living “babies” that hatch from a brood sac. When the environment is inhospitable, brine shrimp switch to the production of cysts, which are well known to most experienced aquarists. The tough, indigestible covering of the cyst can be removed during a process called decapsulation. In the section, you will learn why brine shrimp are an excellent aquarium fish food, why decapsulated cysts are preferable and how to use brine shrimp as live feed.