Copepods play a vital role in reef tanks. They keep your tank clean on a microscopic scale, add to the aesthetics, and provide a reliable food source. But many new reef tank owners hesitate to add them, thinking they may upset the balance.

Copepods can be introduced to a tank by dispersing them in a reef tank without light and water current. Once settled, providing ample microalgae and phytoplankton to feed on will help them thrive. To increase the breeding rate, providing more hiding spots would suffice.

Instead of exact measurements, keeping copepods is more reliant on getting a few basic steps right. The rest comes from experience. So, to help you understand the basics, I’ll provide a succinct explanation of their nature, habits, and how to keep them in a reef tank.

What Are Copepods?

Copepods are lilliputian crustaceans that are typically 1-2 mm in length and are commonly found in both freshwater and saltwater environments. Copepods can be planktonic, parasitic, or even bottom-dwellers in the oceans.

The most common species of copepods added to a reef tank are Tisbe Biminiensis, Tigriopus Californicus, Apocyclops Panamensis, and various species of the Oithona genus. Even without intentionally introducing them to your reef tank, copepods may come to inhabit your tank, especially if you have refugium in your sump.

Why Should I Consider Adding Copepods To My Reef Tank?

Adding copepods to your reef tank can grant these 3 benefits.

  • Natural Food Source: Copepods serve as a natural food source for your fish, shrimp, and corals in the reef tank. Tisbe Biminiensis are liked by even the pickiest eaters, Tigriopus Californicus are rich in Omega-3, and Apocyclops Panamensis are rich in fatty acids and Astaxanthin. Astaxanthin is a compound that helps enrich the coloration of your fish and corals.
  • Natural Cleaners: Copepods eat algae, detritus, diatoms, and other waste produced in your reef tank. Even if you have snails and cleaner fish in your reef tank, copepods can clean on a microscopic scale that remains inaccessible to you. They are great at getting into crevices and niches between rocks, corals, plants, and corners that no one else can reach.
  • Increasing Biodiversity: Adding copepods to your reef tank will increase its biodiversity. Having a biodiverse reef tank can add natural filtration, introduce food chains, and lower toxin and waste production. It also adds to the aesthetics of your reef tank.

How To Tell If My Reef Tank Has Copepods?

Odds are your reef tank already has copepods. They can get transported into your reef tank by introducing new fish, frags, snails, or even plants. It’s almost impossible for a tank not to have a population of copepods, even if you haven’t manually introduced them to the tank.

However, if you want to ascertain whether you have any copepods in your tank or not, it’s quite easy. Shine a light at the nooks and corners of your tank and your sump at night, especially with the refugium light off. If you see any scattering or movement, you can be sure that you have copepods.

How To Grow Copepods In Reef Tank?

If you want manually add and grow copepods in a reef tank, you have to consider a few prerequisites.

  • System Volume And Carrying Capacity:  Based on how much water your reef tank holds, the environment, food sources, and roaming and hiding space available in your tank, it will only hold a specific amount of copepods and no more. Your tank may already be at max carrying capacity.
  • Water Flow: If you have powerful mechanical pumps or wave generators in your reef tank, then you need to be cautious before putting copepods in. The powerful water currents would inhibit movement, feeding, and breeding for copepods.
  • Harsh Lighting: While copepods don’t have aren’t averse to light, harsh lighting can lower their odds of successfully adjusting in your reef tank. Light exposes them to the fish and corals in your tank, and they may be hunted down before they can settle. However, once adjusted, the copepods should have no trouble with light.
  • Food Source: While copepods can survive on waste, detritus, and diatoms, their preferred food is microalgae. It’s recommended to have a refugium housing microalgae such as species from Chaetomorpha, Caulerpa, or Hakimeda genus. Phytoplankton is also another food source for copepods, but much of it is expelled through mechanical filtration in your reef tank.

Introducing Copepods To A Reef Tank

Now that I’ve discussed what you should be wary of let’s discuss how you can introduce copepods into your reef tank. Here are the steps you can take to successfully include copepods in your reef tank.

  • Purchase a mix of Tisbe Biminiensis, Tigriopus Californicus, Apocyclops Panamensis, and any species of Oithona. To start with, buy 2 portions of 16 ounces of these species mixed in.
  • Check if the copepods are alive by checking the jar for any movement. Check if you get a rancid smell when you open the jar and if there is a noticeable amount thick layer of grey goop at the bottom. If there is no goop or no smell, your pods are alive and well.
  • Store one of the portions in the freezer. This will slow down the metabolism of the pods, and they will last longer. Use only one to ensure that your process is effective.
  • If you have mechanical filters and wavemakers, turn them off first. Drop the copepods at night during lights out so that they can find places to hide and settle before they are eaten. Then simply dump the contents of the jar in your tank, and you have copepods.
  • Check for copepod activity for the next few days, and if successful, then add the other jar. If not, then check if they are getting eaten or if you don’t have enough food sources in your tank.

It’s recommended to dump close to half of the copepods in the refugium in your reef tank. This way, they can directly access the microalgae in your tank. It doesn’t matter if your refugium is upstream or downstream in your sump, as the mechanical filter blades can’t harm your pods.

Growing The Copepods

While it’s easy to chuck some copepods in your tank every now and then, growing them in your tank can be a fun challenge. Copepods will grow healthy and breed if you have phytoplankton and microalgae in your tank. In most cases, your refugium will have either Chaetomorpha or Caulerpa. You only have to add phytoplankton manually.

Adding phytoplankton isn’t an exact science, and you have to figure out how frequently you have to dose your tank from experience. Most users prefer to play it safe and add phytoplankton daily, and many prefer to do so every other day. However, for a 75-gallon reef tank with a 30-gallon sump, you can get away with dosing it once a week.

To increase your copepod population and ensure you’re always at full carrying capacity, plan where you’ll deposit the pods in your tank. Arrange for more hiding spots and rocky rubble for increased surface area. Dosing phytoplankton more often will also help your cause.


It isn’t complicated to introduce and nurture copepods in your reef tank. All you need is a lot of experimentation and patience to figure out an effective process. Experience is your best friend here, and it doesn’t take a lot of effort to get started. If you don’t want to risk causing any issues, simply keep dosing your tank with phytoplankton, and keep your tank stocked with microalgae.

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