The Salty Side: Saltwater Aquariums for Beginners

How to Culture Copepods

Copepods saltwater aquarium

In this article I will cover a few of the most common questions such as how to culture copepods, whether they are beneficial for your tank or not, and more! 
  
If you own a saltwater aquarium or are thinking of owning one, you will certainly hear a fair bit about them in the fishkeeping world.

What are copepods?

Copepods (subclass Copepoda) are tiny shrimp-like crustaceans that live in both salt and freshwater.  They live on phytoplankton and are a valuable food source for fish larvae in particular, but most fish, seahorses, invertebrates etc will dine on them.  In a saltwater aquarium they are imperative if you have a Mandarin goby or Scooter blenny.  

Copepods are particularly visible at night when the majority of their predators are asleep.  If you shine a light in the tank, a red light works best, you might see plenty of these little creatures scuttling around on the sand, rocks and glass. If you have a lot of them, it is a good sign!  It shows a thriving ecosystem meaning that you have a healthy tank.  

What do you need to culture copepods?

There are a few things you will need to get things started, all of which are pretty inexpensive, and available from Amazon. Links are provided below.

1. A suitable container to accommodate copepods

Copepods are not at all fussy. You can culture copepods in an old fish tank, a half gallon glass jar, or even a plastic bucket.

2. Lighting to culture copepods

Copepods are just as happy on a windowsill with natural lighting, as they are with artificial lighting such as a grow lamp

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3. A fresh mix of salt water to start the culture

Do not be tempted to use the water from your aquarium. Mix up some new salt water for the best chance of success. 

4. Creating water movement in the culture

You will need an air pump and air-line to keep the copepod culture from going stagnant, and to give the water a constant addition of air. Make sure you add an air regulator to the line to manage the air flow, and finish it off with a non-return valve to prevent back flow.

5. Add copepods to start your culture

Finally, you will need the copepods themselves to get things going. A good purchase is the AlgaeBarn Live Copepod & Phytoplankton Combo Pack. You will also need Spirulina powder to keep those pods happy!

AlgaeBarn Live Copepods & Phytoplankton Combo Pack Tisbe & Tigriopus Pods + Live Phytoplankon (16oz)
  • Seed Your Aquarium & Feed Finicky Fish
  • Contains nutritious Tigriopus & Tisbe Copepods plus 4 strains of live phytoplankton
  • Premium live food for Mandarin Dragonets, Seahorses, LPS, SPS & NPS Corals, Wrasses, Anthias, Pipefish, Clown Fish, Blennies, Clams, & other Finicky Fish & Inverts

The method I use to culture copepods

There are a few ways to successfully culture copepods at home. Some I have tried and failed. This method has worked for me every time. 

1. Set up your equipment

Using your freshly mixed salt water, fill your fish tank or container up to the 3/4 mark. Use a permanent pen to mark the level. This will help if you need to top it up due to evaporation.

Set up your air-line and add your lighting if needed.

2. Add the phytoplankton

Pour in just enough phytoplankton to turn the water slightly green. Too much will foul the water.

3. Adding the copepods

Next add the live copepods.  If they have been kept in the fridge, allow them to adjust to room temperature before adding them to the container. 

Copepod Breeding for Saltwater Aquariums

Make sure you place your container away from areas where they may experience extreme temperatures such as near a radiator or in a cold utility room or garage. 

In the first few weeks you won’t see much happening but keep feeding lightly with a pinch of spirulina or a small amount of phytoplankton and you will suddenly find you have hundreds!  

In larger containers, water should be changed once a month, and more often for a smaller container. 

Culturing copepods isn’t that hard.  However, overfeeding is a common reason many cultures fail.  As long as the water is only lightly coloured and not a very dark green, then you will have more success.  Similarly, the water needs to remain coloured so there is always food available.

The following tips made breeding more successful:

I had repeatedly tried, unsuccessfully, to try and breed copepod.  However, it was not easy.  After trying once more, I had thousands breeding, certainly enough to keep my mandarin happy and well fed.  

Here is what I learned:

  • Although I have tried feeding with both spirulina and phytoplankton, I have found spirulina to be the most successful.  A small pinch when the water looking clear or typically every few days, depending on how many copepod there are.

  • Keep the lid off the container.  I previously used to leave the lid on to stop evaporation but I think that might have hindered their breeding.

  • Suction out the gunk at the bottom of the container (ie. do a water change) every 3 weeks.  Remember to top it up again with freshly mixed salt water.  

  • Mark the level of the water with a permanent marker when you first set up your container.  Then you can see how much has evaporated and top up whenever necessary with RO water. 

Hopefully these tips will help you a great deal.  I wish I’d known them when I first starting breeding copepods.  

Below are a few common questions asked about these little crustaceans.

culturing copepods saltwater aquariums
Before feeding for the first time

How did copepods get in my tank?

They can end up in your tank in a variety of ways.  When buying and placing live rock into your reef tank, it may harbour a number of pods hiding in the cracks and crevices.  Corals and macroalgae, such as chaetomorpha (chaeto for short), are also ways in which they can end up in your tank. 

cheatomorpha for copepods

What do copepods do?

They clean rocks, sand and glass by consuming organic waste such as bacteria and microalgae, such as coralline algae.   

As an important part of the food chain, they feed the fish and invertebrates in your tank.  As mentioned above, they can also be an important food source for Mandarin Dragonets (see this article on how to feed Mandarin Dragonets) and Scooter blennies.  They therefore make easy pickings for these slow movers.    

How big do copepods get?

They generally only grow to 2mm in size.  In the wild they can grow bigger but it is unlikely in an artificial environment such a saltwater aquarium.  

Are copepods good for my tank?

Copepods are at the lower end of the food chain and as such, are a vital food source for other smaller living organisms such as fish larvae.   They are high in protein and free amino acids.

They also make up part of a balanced ecosystem in your aquarium. They feed off detritus and organic waste such as microalgae and bacteria helping to keep these under control.

Do copepods live in sand?

As adults, yes. Not only do they live sand but you will also find them on rocks and the glass of your tank.

Before that, during the larval stage, they swim about freely.  This is why a refugium or separate container to breed copepods in can be beneficial in reproducing them at home.

The larvae will not stand a chance with ever-hungry and opportunistic fish in a tank.

What fish eat copepods?

Most fish will eat them if they come across them but the following in particular love them:

  • Mandarin Dragonet

  • Scooter Blenny

  • Six Line Wrasse

  • Butterfly fish

  • Chromis

copepods mandarin goby fish

What do copepod eat?

Copepods are the basis of the food chain in the tank and they too need to be fed.  

Larvae feed on phytoplankton.  As well as phytoplankton, adults feed off organic waste and detritus.

To ensure your population keeps on growing and thriving, you can add phytoplankton to your aquarium.  Phytoplankton can be bought from your local lfs or online.

Habitat

Copepods can live anywhere as long as there is water and light.  They can even thrive in freezing temperatures! They are found in both saltwater and freshwater.  

In a saltwater aquarium copepods need a place of refuge such as live rock and in a refugium, a large bunch of macroalgae like chaetomorpha. 

Without live rock in the main tank, they would not last long and be quickly eaten by fish or invertebrates. 

Copepods in saltwater aquariums

Remember that a good source of phytoplankton is necessary in order for pods to survive and reproduce.

Where to buy copepods

You can buy pods from online retailers or from your local fish shop (lfs) and introduce them into your tank. 

Add the copepods at night.  They will need to hide and settle otherwise they’ll be eaten straight away. 

Try release them as close to the sand as possible. This can be done by using a long piece of tubing or pipe and pouring the pods in at the top of the pipe.  They will at least have a better chance of finding somewhere to hide and therefore have a greater chance of survival. 

Copepods for sale

Conclusion

Now you know how beneficial copepods are in a saltwater aquarium you may want to start culturing your own.  I would also definitely recommend running a refugium to support a copepod population.

Hi, my name is Craig.
I am the owner of The Salty Side.
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