Cyclops Profile and Culture Guide

Cyclops Profile and Culture Guide

Culturing live food, such as Cyclops, can be a good way to provide a nutritious and diverse diet for your aquatic pets while also saving money on live food purchases.

Cyclops are small freshwater crustaceans that are widely used as live food in the fish-keeping hobby. These tiny creatures can be a great addition to your aquarium’s food rotation, offering a high level of protein, essential fatty acids, and vitamins

This article provides comprehensive information on Cyclops, including their life cycle, behavioral characteristics, diet, as well as the materials and requirements necessary to culture them in an aquarium.

Cyclops as Live Food

Cyclops can be a nutritious and beneficial live food for a variety of aquatic animals, including:

  1. Fish: Many types of fish, particularly fry, small and juvenile fish, can benefit from a diet of Cyclops. Examples include guppies, tetras, and bettas.
Warning: Cyclops are classified as predatory, which may lead to issues when kept with egg scatterer fish. It has been observed that Cyclops have been known to consume eggs and even attack newly hatched fry, which can be particularly vulnerable during their first few hours of life.
  1. Amphibians: Aquatic amphibians such as newts and tadpoles will definitely benefit from a diet of Cyclops as well.
Note: No matter how good the diet is for your fish and other aquarium pets, it should not rely solely on one type of food. Even if the diet is based on Cyclops, which is a great food source, it is important to vary and diversify your pets’ diet to ensure their health and well-being.

Nutrition Value of Cyclops

Although the specific nutritional content of Cyclops can vary depending on the species and the environment in which they are cultured, but in general, they are rich in protein, and contain some essential fatty acids, lipids, and other important nutrients.

Feeding fish with Cyclops will never cause obesity, as these crustaceans are digested faster than fish can get saturated with them. The chitinous shell of the Cyclops is not digested and serves as valuable ballast material that stimulates peristalsis in the fish intestine.

The fish that feed on Cyclops are incredibly vibrant in color!

Components Nutrition value (Dry weight %)
Protein 40 – 60 %
Fatty acids 12 – 14%
Crude fibre 1 – 2%
Ash 10 – 20%
Carbohydrates 5 – 10%

What are Cyclops?

Cyclops are small freshwater copepod crustaceans that belong to the order Cyclopoida, which contains over 1500 species.

These species vary in size and distribution, but they all share similar characteristics such as a single eye, a segmented body, and the ability to swim using small appendages.

Habitat and Distribution of Cyclops

Cyclops are usually found in freshwater habitats around the world, including lakes, ponds, marshes, swamps, ditches, irrigation canals, etc. These crustaceans prefer shallow waters, where they feed on algae, bacteria, and small aquatic animals such as rotifers and protozoa.

Cyclops are known to be particularly abundant in eutrophic, or nutrient-rich, bodies of water, where they can form large populations and play an important role in the aquatic food web.

Note: In reality, Cyclopoid copepods are cosmopolitan; some species can be found even in brackish waters or ground water habitats.

Description of Cyclops

Cyclops Profile and Culture Guide - anatomy Cyclopoida

  • Size. Cyclops are small, freshwater crustaceans that are typically range from 02 to 0.08 inches (0.5 to 2 mm) in length.
  • Color. Their body is mostly transparent, allowing for easy observation of their internal organs. However, depending on the color of the food they eat in the aquatic environment, they may have a gray, green, yellow, red, or brown
  • Body structure:Cyclops have elongated body with a single, large eye located near the front of the head. Cyclops have antennules (cephalic appendages) that they use for swimming; the antennae are unbranched. They have 4 pairs of developed legs and males have a fifth pair that is modified for grasping the female during mating.  
  • Internal anatomy. Cyclops do not have a heart or circulatory system. Instead, their organs are bathed in colorless hemolymph, which is propelled by the pulsation of the gut. They breathe through their entire body surface (no gills). Their nervous system only consists of a head “brain” and a ventral nerve cord that forms a “ladder”; there are no ganglia.

The female differs from the male in that she carries on both sides of her abdomen wide, flat, egg-filled pouches that give her a somewhat winged appearance.

These tiny creatures are named after their distinctive feature – a single eye located in the center of their head. Another common name for Cyclops is “Water Flea,” which is attributed to their physical resemblance to land fleas during their early stages of development.

Behavior of Cyclops

Movement. Cyclops are fast horizontal swimmers. They move through the water with solitary jumps, pausing briefly as they hover before gradually descending downward. They then propel themselves forward and upward again with another burst of energy.

These crustaceans are extremely agile and quite difficult to catch. In the water, they move in sudden leaps, with a burst speed of up to 75 mm/second!

Cyclops tend to hover near the bottom, making short, twitchy jumps to move from place to place. Occasionally, they also cling to surfaces, particularly glass, and crawl along it.

Resting. Like many aquatic creatures, Cyclops occasionally rest or remain motionless in the water. During these periods of rest, they may sink to the bottom of the container or cling to the sides of the tank.

Light. Cyclops are sensitive to light. It attracts them.

Live Cycle of Cyclops

The life cycle of Cyclops involves several developmental stages, starting from eggs, then hatching into nauplii, copepodite, and finally reaching maturity.

  1. Egg Stage: The female lays eggs, which are attached to the substrate or other objects in the water. The eggs are usually translucent and can hatch within a few days.
  2. Nauplius Stage: After hatching, the Cyclops larvae emerge as nauplii. Nauplii are small and have only three pairs of appendages (one pair of antennae and two pairs of swimming legs), a head, and a tail but no true thorax or abdomen. In general, Nauplii have very little resemblance to their parents. They need to undergo several molts before reaching the next stage.
  3. Copepodite Stage: The nauplii molt and develop into the copepodite stage. At this stage, the Cyclops have developed more pairs of appendages and can swim more efficiently.
  4. Adult Stage: After several more molts (about 15 – 30 days), the Cyclops reach the adult stage. At this stage, they have fully developed reproductive organs and can reproduce.

Livespan of Cyclops

The lifespan of Cyclops can vary depending on the species, nutrition, and environmental conditions.

Some species may complete their life cycle in a matter of weeks, while others may take several months. In general, their lifespan range from 30 – 80 days.

Reproduction of Cyclops

According to the study, Cyclopids are dioecious, which means that they are sexually reproducing crustaceans.

Cyclopoid copepod females store the sperm in their seminal receptacles and produce multiple egg clutches from single fertilization sometimes for several weeks or even months. Basically, it was observed that remating is rare and almost unnecessary in cyclopoids.

The fertilized eggs are carried in sacs on the female’s body until they hatch into nauplii.


Reproduction in freshwater copepods is influenced by species-specific factors, including nutrition and temperature.

Under unfavorable conditions, Cyclops may have a diapause. This is a period of dormancy in which the development is temporarily suspended. It can help to ensure the survival of the species in adverse conditions.


Basic Set-Up for Cyclops Culture 

Setting up a culture for Cyclops, is relatively straightforward and requires only a few basic materials, such as:

  • Cyclops starter culture,
  • Small culture container (e.g. plastic or glass jar, aquarium)
  • Aeration system (e.g. air pump, bubbler stone)
  • Light source (e.g. fluorescent light, natural sunlight)
  • Culture food (spirulina, phytoplankton, rotifers, other small copepods, etc.)


  1. Fill the culture container with clean and dechlorinated water.
  2. Add an aeration system to the culture container, such as an air pump.
  3. Place the container in a well-lit area, either under a fluorescent light or in a spot that receives natural sunlight.

Although Cyclops do not require light too much, their prey does! Thus, providing adequate light is also important.

  1. Let algae and biofilm grow in the culture container before adding Cyclops. You need to wait for at least a few days. Do not drop them off right away.
  2. Add a starter culture of Cyclops.
  3. Feed the Cyclops with a culture medium such as yeast, wheat flour, or oatmeal. These foods provide the Cyclops with the nutrients they need to grow and reproduce. Start with a small amount of food and gradually increase the amount as the Cyclops population

Overall, setting up a culture for Cyclops is relatively simple and can provide a reliable source of live food for your fish. By following these basic steps and monitoring the culture regularly, you can ensure that your Cyclops culture remains healthy and productive.

Tank size:

The optimal tank size for Cyclop culture can vary depending on the number of Cyclops you want to culture and the space you have available.

Generally, a container that can hold at least a gallon (4 liters) of water is sufficient for culturing a small population of Cyclops.


Generally, most species of Cyclops thrive in temperatures between 73-78°F (23-25°C). Sudden fluctuations in temperature can stress the Cyclops and lead to decreased growth and reproduction.


Even though they are sensitive to light (it attracts them), Cyclops are not photosynthetic organisms and do not require specific lighting for growth and reproduction.

However, providing some form of light can be beneficial for the overall health of the culture. Light will lead to the growth of algae and other small organisms that will be consumed by Cyclops, which will beneficially impact your Cyclops culture.

The light should be on for 8-12 hours per day

Oxygen and Aeration:

Maintaining adequate oxygen levels and providing proper aeration is important for the health and reproduction of the Cyclop cultures.

Cyclops require a constant supply of dissolved oxygen to survive, and the levels of oxygen in the culture can fluctuate rapidly due to changes in temperature, feeding, and other factors.

The optimal oxygen level for Cyclop culture is between 5-8 mg/L.


No special requirements. Cyclops cultures typically do not require a substrate, as they are free-swimming organisms.

In addition, bare-bottom tanks are easy to regularly clean and maintain to prevent the buildup of excess waste and debris. This can help to promote a healthy and productive culture and prevent the growth of harmful bacteria and other microorganisms.

Note: Instead of the substrate, you can use dead leaves. Once the leaves are in a tank, a multitude of microorganisms will begin to colonize them creating biofilm that will also be used as a food source by Cyclops.


Filtration is optional if you have a limited budget.

For larger-scale cultures and in the long run, it will be better to have at least a simple filtration such as a sponge filter.

Feeding Cyclops Culture

Contrary to popular belief, Cyclopes are not filter-feeders. In reality, Cyclopes are mostly predatory creatures that primarily feed on simple organisms such as phytoplankton, rotifers, other copepods, young mosquito larvae, eggs, and even small crustaceans.

In addition, Cyclopes are known to be efficient predators, able to consume slightly larger prey such as Daphnia or even tiny fry.

Note: A single copepod can consume several thousand phytoplankton per day. It was also observed that Cyclops feed mainly on young 1st and 2nd instars, and if the larval mosquito density is very high, they may consume only part of the prey’s body and then attack another prey, being able to lead to the death of up to 30–40 larvae per day.

Therefore, to culture Cyclops successfully, it’s important to provide a nutritious and varied diet that meets their nutritional requirements.

Feed the culture with green algae, powdered spirulina algae mixed with a little water every day or two.

It is important to understand that the success of Cyclops reproduction heavily relies on their nutritional intake. A balanced and nutrient-rich diet is crucial to their growth and overall health.

Harvesting Cyclops

Harvesting Cyclops is a relatively simple process. You need a fine mesh net or sieve.

The net can be gently passed through the culture, collecting the Cyclops as they swim into the net. The collected Cyclops can then be rinsed with fresh water and transferred to a separate container for further use.

When to harvest?

To determine the best time to harvest, it’s important to monitor the culture regularly for signs of growth and density. Once the Cyclops have reached a suitable density, they can be collected.

This may take several weeks or months depending on the specific culture conditions and the initial starting density of the culture.

Storing Cyclops

Storying Cyclops culture can be problematic in home conditions, thus, it is not recommended.

Overall, it’s best to use Cyclops immediately after harvesting.

Cyclops Culture Compared with Other Live Foods

In my opinion, compared to other live foods, culturing Cyclops is not the best option unless you are doing it as a personal challenge to prove your skill sets, or out of curiosity.

The main Cons include:

  1. Hard to find clean Cyclops starter culture.
  2. Cyclops have a much lower caloric value than bloodworms, Tubifex worms, or Blackworms.
  3. Cyclops do not reproduce as fast as daphnia or Brine Shrimp and cannot be harvested in large quantities
  4. These copepods have specific dietary needs (they are mostly predatory).

Overall, culturing Cyclops at home is a simple and cost-effective way to provide live food for your fish. With some basic materials and a little bit of care, you can create a thriving Cyclops culture that will provide a nutritious food source for your aquatic pets.

In Conclusion

Cyclops are small freshwater crustaceans that can be used as live food for a variety of aquatic animals, including fish and amphibians.

To successfully culture Cyclops, it is important to provide optimal conditions in terms of water quality, temperature, lighting, and feeding.

Even though compared to other types of live foods, Cyclops have some disadvantages, it can still be a rewarding and beneficial activity for aquarium hobbyists looking to provide a diverse and nutritious diet for their aquatic pets.

Related articles:


  1. Hołyńska, Maria, and Łukasz Sługocki. “Freshwater microcrustaceans (Copepoda: Cyclopidae) on islands: a review.” Hydrobiologia850, no. 1 (2023): 183-201.
  2. HO, Y. NSKA. “Revision of the Australasian species of the genus Mesocyclops Sars, 1914 (Copepoda, Cyclopidae).” In Annales Zoologici, Warszawa, vol. 50, pp. 363-447. 2000.
  3. Veronesi, Rodolfo, Marco Carrieri, Bettina Maccagnani, Stefano Maini, and Romeo Bellini. “Macrocyclops albidus (Copepoda: Cyclopidae) for the biocontrol of Aedes albopictus and Culex pipiens in Italy.” Journal of the American Mosquito Control Association31, no. 1 (2015): 32-43.
  4. Phong, Tran Vu, Nobuko Tuno, Hitoshi Kawada, and Masahiro Takagi. “Comparative evaluation of fecundity and survivorship of six copepod (Copepoda: Cyclopidae) species, in relation to selection of candidate biological control agents against Aedes aegypti.” Journal of the American Mosquito Control Association24, no. 1 (2008): 61-69.
  5. “Small Is Beautiful, Especially for Copepods – The Vineyard Gazette”. Archived from the original on 2018-09-07. Retrieved 2018-09-07.

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