How to breed copepods in an aquarium?

Plague for some, blessing for others! If you are new to the world of aquarism, copepods will certainly scare you at first, as you still have no idea what they are and what they can do.

Today, we are going to discuss a little about these amazing creatures and show you how to raise them in your aquarium.

10 fish to put in aquariums…

What are copepods?

Simply put, copepods are small crustaceans that are practically ubiquitous. They thrive in both salt and freshwater environments, and you can find them everywhere.

The reason this might sound like a novelty is because you can’t really see them. Well, you can, but they’re tiny, just a few millimeters, and almost transparent, making them virtually invisible to the naked eye.

These tiny organisms vary greatly in terms of biology, as some live on the ocean floor, others inhabit shallow marine waters, and several others are parasitic in nature. But today, we’re going to discuss the “standard” copepods that are likely to inhabit your aquarium and why they are actually beneficial to your ecosystem.

More specifically, we will discuss the copepods of coral reef aquariums, as these are the ones that should interest you the most. That said, what applies to marine copepods applies to freshwater ones too – be warned!

What do copepods eat?

Aquarium copepods specialize in consuming phytoplankton and benthic residues (located in the ecosystem substrate), as well as fish and algae residues.

These voracious creatures are considered the sea locusts due to their uncontrolled appetite and eating behavior. To give you an idea, copepods consume individual phytoplankton cells and can devour more than 370,000 cells in 24 hours. In addition, copepods are very active swimmers, with a copepod covering a volume of water of at least 1 million times its body volume every day.

Generally speaking, they are relentless in search of sustenance, which makes them a great addition to any marine or sweet mount. They will also spread quickly if food is plentiful, which may not be ideal due to the impact on aesthetics in the aquarium. After all, the water just won’t look the same with all those tiny organisms swimming around.

So I understand why most experienced aquarists go crazy and want to get rid of them. However, as you will soon see, this is not advisable.

How to start breeding copepods in an aquarium?

An even better question would be – why would you start a copepod aquarium? The answer is simple: because you need them!

These microcrustaceans consume debris, phytoplankton, and algae that grow on aquarium substrate and various other hard marine surfaces. Its activity keeps the aquarium water clean and contributes to a cooler and more stable environment.

This is great for your corals, fish and virtually all aquarium inhabitants. Not to mention that copepods are harmless as they do not affect the water quality and do not cause any harm to fish. In addition, many species of fish actively hunt and eat them, as they are rich in protein and fat.

Now that you understand the role and importance of copepods, it’s time to start your own culture. This is necessary due to the appetite of many fish for these little guys, which can lead to the extinction of copepods in your aquarium.

To start your own copepod culture, consider the following requirements:

1. Choose the right container

The size and type of container you use depends on the size of your copepod culture. However, I recommend that you purchase a 20 liter aquarium to raise them.

Read More – Pictus Catfish Complete Care Guide, Size, Tank Mates and More

2. Setting up the aquarium

You can set up this aquarium with a sand substrate and use live rocks to create a more natural filtration system. One air pump it is also necessary to ensure that there is movement in the water. I advise against using a standard filtration system. Copepods are small organisms that can easily be sucked into the filter. An air pump, combined with a handful of live rock, should do all the filtering work.

3. Add a food source

I recommend microalgae as a long-term food source for your copepods. Therefore, you can set up the aquarium to promote the growth of these types of algae while accommodating them at the same time. Phytoplankton is another source of nutrients, especially since it’s easy to grow at home.

Just remember to constantly check the levels of ammonia and nitrite in that aquarium. That’s because copepods never overeat, which means all excess food breaks down in the water.

4. Aquarium lighting

Copepods don’t need bright lights, so keep the lighting dim to create the perfect environment for them. Just make sure there is enough light to promote microalgae growth, as they are one of the main foods available to these creatures.

5. Watch out for the temperature

Copepods are comfortable in temperatures around 22 – 27°C. This temperature is considered standard for most fish, so it shouldn’t be difficult to reach and maintain it. Do not let the temperature exceed 29°C, as this will cause the mass death of your copepod population.

Once the environment is set up, you can move on to the next phase, which is maintenance.

How to maintain a copepod culture?

Fortunately, the maintenance part is almost minimal, as an optimized copepod ecosystem is pretty much automatic. You only need to perform monthly water changes to preserve water quality and refresh the system.

Copepods don’t produce much waste. In addition, you will collect the small crustaceans regularly to feed the fish or replenish the population in the main aquarium.

You only need to perform extra water changes in case of overfeeding, which can result in water spikes. ammonia and nitrite.

Other than that, their involvement is minimal, requiring only general oversight.

How do copepods reproduce?

The reproduction system of copepods is quite simple. They reproduce sexually, with the male chasing and inserting his sperm into the female. There, the sperm will fertilize the eggs, which the female will place in a bag and deposit them somewhere in the aquarium.

The larvae that hatch are called nauplii, which represent the first stage of the copepod’s life cycle. These nauplii undergo a molting process to transform into copepods, which are essentially young copepods. These then mature and become adults, redefining the entire life cycle.

Copepods reproduce very quickly, but the entire life cycle can last several months. After all, these tiny crustaceans can live between 6 months and a full year in good conditions.

How do I harvest copepods?

All you need is a siphon with a very fine mesh attached to the water outlet for the job. The mesh will trap all copepods for easy collection.

You can get as many as you like and allow the rest to go about their business to multiply and replenish the ones you’ve collected.

How do you know if the copepod culture is dead?

You’ll know there are no more copepods alive if you don’t see any of them swimming anymore, simple as that. As they die, their bodies accumulate en masse in the substrate.

If you only have a handful of copepods swimming around with hundreds or thousands of dead at the bottom, that’s a sign that the culture is almost dead.

You can consider the culture officially dead if there are no more live copepods visible. Fortunately, this scenario is unlikely if you manage the culture correctly.

monitor the water quality constantly adjust its parameters based on the needs of your copepods and ensure enough food and your culture will thrive.

Which fish feed on copepods?

Given that copepods are ubiquitous in virtually any aquatic system, it’s safe to say that nearly all fish consume them. Some, however, eat them more effectively than others and tend to hunt them all the time.

Among the most popular copepod killers we can include the clown fish, rasboras, tetras, guppies and many others.


Copepods are a welcome addition to any aquatic setting, but you should be a little careful with their numbers so you don’t overpopulate your aquarium.

If you want to control the population of copepods, just add a few eaters of them to the aquarium and in a short time their number will decrease.

Then, create a separate culture to keep the crustacean population alive in case your fish overdosage a bit.

Read More = Can Betta Fish Live in an Unfiltered Aquarium?