Cyclopoid Copepods (Apocyclops panamensis)

The Importance of Cyclopoid  Copepods

Marine aquarium hobbyists are increasingly coming to understand what professional aquaculturists have known for decades—cyclopoid copepods are a superfood. This should not be surprising, though, in light of their major ecological role in nearly every marine environment. The copepods are an astoundingly diverse group, representing all major aquatic biomes (even in wet holes in trees). They are, in fact, at the base of nearly every zooplanktonic food chain. This is for two reasons. For one, they are incredibly abundant; actually, they may be counted among the most numerous multicellular animals on the planet. Secondly, they are a major source of essential organic compounds for the many creatures that feed on them.

The Rise of Copepod Cultivation

However, the difficulty in culturing copepods in mass has somewhat restricted their availability to the general public. Fortunately, owing to refined cultural techniques, this has been changing. Nowadays, live copepods are a staple item at better aquarium shops. Aquarists are increasingly building and replenishing copepod populations in their regular maintenance routine. And, given the widespread positive results reported throughout the hobby and industry, many eyes have been following new developments in the culture and uses of new copepod species. Of these, Apocyclops panamensis is a very promising candidate.

Diversity in the Marine Aquarium

Various forms of tiny crustaceans may be found in most established marine aquaria. And these do indeed exert a generally positive impact on the system’s health. So why add other species? Put rather simply, not all “pods” are the same. The term pod can describe thousands upon thousands of species (mainly copepods and the related amphipods), each with its unique behaviour, life cycle and nutritional profile. A mind-blowing 13,000 copepod species are placed into eight orders. The three dominant orders belong to the calanoid, harpacticoid and cyclopoid copepods. While all three have been used successfully in aquacultural applications, the cyclopoids have thus far been the least investigated. Nevertheless, a few of the 700 cyclopoid species, such as the red snapper, have proven to be highly useful in the larviculture of fish species.

Spotlight: Apocyclops Panamensis

Apocyclops panamensis stands out with characteristics ideal for marine aquarists. This species thrives in temperate and tropical waters due to its eurythermal nature, allowing it to withstand varied temperatures. Additionally, its euryhaline trait enables survival and reproduction in freshwater to full seawater. Adults, which are benthic, settle on the substrate, while their younger counterparts float as plankton. Predominantly omnivorous, they have a special inclination towards diatoms and cyanobacteria. Their rapid reproduction sets them apart, with adult sizes between Tisbe and Tigriopus. These adults become prime targets for small fishes, while their offspring serve as nutritious feed for zooplanktivores, packing twice the free amino acid content compared to Artemia.

In a conventional home aquarium, Apocyclops proves invaluable. They’re resilient, aiding in reducing microalgae growth, a common issue reef aquarists face. Their impressive reproductive speed, surpassing even Tisbe and Tigriopus, promises a balanced and thriving environment. Interestingly, they’re efficient but don’t outcompete calanoid or harpacticoid species. This allows filter-feeders like feather duster worms and predators like mandarin fish to thrive. Rich in proteins, free amino acids, and unsaturated fatty acids, they also boast of astaxanthin, a pigment enhancing the colours of fish, corals, and other marine life. Being under 100 micrometres, the young are a treat for many filter feeders. In essence, the presence of Apocyclops panamensis amplifies the health, cleanliness, and natural balance of any aquarium.

Apocyclops panamensis boasts features appealing to all marine aquarists:

  • Adaptability: Thrives in varied temperatures and salinities, suitable for temperate and tropical waters.
  • Diet: Prefers diatoms and cyanobacteria, though it possesses an omnivorous palate.
  • Reproduction: Among copepods, they reproduce exceptionally fast, providing a consistent food source for numerous marine species.
  • Benefits for Aquarists: Their resilience and rapid reproduction rates improve aquarium health, while their inability to outcompete other copepods ensures biodiversity.

Cultivating Apocyclops Panamensis

As far as copepods go, Apocyclops panamensis is pretty straightforward to culture. It grows well on various foods: Spirulina, Chlorella, Tetrasalmus, and Nannochloropsis. Of course, the nutritional value of each batch is largely dependent upon the quality of its food. Thus, its diet should be nutrient-rich and complete. Smartly mixed microalgal feed products serve this purpose well. While the species is known for its impressive productivity, real-world reproductive rates depend upon various environmental conditions (temperature, food availability, population density, etc.). Its short generation time is particularly impressive because it undergoes numerous larval stages, moulting after each one, before reaching the benthic adult life stage.


Happily—above all, for those who want a good supply of live copepods but would rather not raise them—small, clean, healthy batches are now regularly available online and in finer local fish stores. In sum, the cyclopoid copepod Apocyclops panamensis is an excellent addition to any population of micro crustaceans. Resilient and fast-growing, it reliably mops up unsightly algal films over the aquarium substrate without dominating its fellow pods. It is an ideal size and nutritional profile as a live feed for some of the most desirable—but notoriously finicky—aquarium species, with colour-enhancing properties. All told a little bag of living Apocyclops panamensis may not cost very much but is nonetheless one of the single best investments a serious aquarist (or any aquarist, for that matter) could make for their tank.

[1] Cano, Roberto, Scarleth Raudez and Evelyn Hooker. 2004. The Natural Diet of Apocyclops panamensis at a Shrimp Farm on the Pacific Coast of Nicaragua. Zoological Studies 43(2): 344-349.
[2] Strottrup, Josianne G. 2006. A Review on the Status and Progress in Rearing Copepods for Marine Larviculture. Advantages and Disadvantages. Among Calanoid, Harpacticoid and Cyclopoid Copepods. Avences en Nutricion Acuicola VIII 333(5): 970-994.
[3] Lindley, L.C., R.P. Phelps, D.A. Davis and K.A. Cummins. 2010. Salinity Acclimation and Free Amino Acid Enrichment of Copepod Nauplii for first-feeding of Larval Marine Fish. Aquaculture 318(2011): 402-406.
[4] Kassim, Zaleha, Akbar John, Lim Keng Chin, Nur Farahiya Zakaria and Nur Hidayah Asgnari. Sustainable Techniques for Selected Live Feed Culture. Terengganu, Malaysia: Intech, 2014.
[5] Stottrup, Josianne, PhD and Lesley A. McEvoy, PhD, eds. Live Feeds in Marine Aquaculture. Oxford, UK: Blackwell Science Ltd., 2003.
[6] Lee, Cheng-Sheng, Patricia J. O’Bryen and Nancy H. Marcus, eds. Copepods in Aquaculture. New York, NY: John Wiley & Sons, 2008.