Copepods are tiny crustaceans that form an important link in the compound yet fascinating marine food chain. These microscopic organisms are members of the plankton food chain and feed on bacteria, phytoplankton, and other tinier organisms. Copepods can be found in many regions; mainly in the deep blue seas and thick rainforests. Copepods are everywhere and in several forms. There are over ten thousand species of Copepods but three dominant albeit recognizable ones – Calanoids, Harpacticoids, and cyclopoids.

In the aquarium and aquaculture industry, copepods are considered a highly rich and reliable source of protein and fatty acid and are Mari-cultured as food for several Large Marine animals. In their natural, unfettered state, Copepods are preyed upon by fishes and whales. This goes without saying that the Copepods play a vital role in most freshwater and marine ecosystems.


Copepods are the most diverse metazoan in the water world – from freshwater to hypersaline regions; copepods are everywhere. Copepods ranges in sizes (from 500 um to 2 mm in length). Copepods possess a cylindrically shaped body with smaller appendages on the head and thorax. Copepods have a unique exoskeleton, a prominent pair of legs that act as an antenna used for swimming. Copepods are usually brown, but few may look reddish due to an accumulation of liquid droplets in the body. Copepods are considered Omnivores as they feed majorly on zooplanktons, algae and bacteria.  Copepods can also act as a controlling measure for malaria by consuming the host mosquito larvae.


Copepods reproduce sexually; which means both male and female copepods are needed for reproduction. Females leave a trail of pheromones which sets the male copepods on a wild hunt. Upon location of the female, the male copepod places a single sperm package on the abdomen of the female copepod. The sperm escapes and penetrates into the body through an opening and is stored in a sac which also houses the fertilized eggs. Fertilization takes place, and the newly hatched Nauplius Larvae is born with only appendages and mouthparts for appendages.


Introducing copepods to the system comes with a lot of benefits. Most marine aquarists will usually try to exploit most of these advantages at the same time, which includes the elimination of detritus elements, and nuisance algae. Copepods also provide excellent nutritional value for numerous fishes and reef creatures. An aquarium without a significant or sizeable amount of copepods is likely to suffer and devolve into a less than optimal condition for aquarium organisms.


Copepods can be cultured in any tank/container. A plastic bucket or a 10-gallon aquarium is a great start. The container/gallon must be able to allow a growing medium which includes live rock, old bio balls, sand amongst others.

The most direct method will be to feed the fishes first and then pour the copepods at night time. You can use a feeding tube or a PVC pipe for this purpose. Copepods do not need a lot of lighting to thrive. 12 to 16 hours of ambient daylight or LEDs will do fine. A stable temperature within the range of 72-82 degrees.

Maintaining or catering to a large number of copepods comes with its little hard work. It’s important to understand that no matter how much effort you exert into creating the most natural environment possible, it’s still going to be relatively unnatural which means there would be unexpected outcomes on some occasions. Some of the hazards or dangers the copepods face ranges from entrapment to irradiation and most importantly – Heavy Predation. A typical reef aquarium contains a large number of fishes and invertebrates capable of consuming hundreds of copepods every day.

So when attempting to revive a failing system with the introduction of copepods, the same consideration should be given and a steady supply of phytoplankton should never be far away. This will prevent the copepods from swimming above their darker recesses in search of food and being consumed by mandarin fishes and seahorses (which is not a bad thing but when in short supply could be).

A feeding regimen should be adopted – dosage and frequency should be modified depending on health state/color of the system.


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