What are Copepods and How Do You Use Them in the Tropical Marine Aquarium

“Cutting edge fish production could be centered around the proper nutrition that could come from copepods.” –Erik Stenn, AlgaGen

Let’s talk a little about live food for marine aquaria, shall we?

Before we get into the actual husbandry practices, I want you to meet Erik Stenn of AlgaGen. AlgaGen, which started as a microalgae producer, is now one of the leading suppliers of rotifers, artemia and copepods for the marine aquarium industry, and, as such, he is a good person to know.

Scott Hughes of Saltwaterfish.com, one of the first retailers to carry AlgaGen products, says, "Algagen has been on the forefront in developing live aquaculutred foods. We saw the potential very early for our business and have been pleased to offer Algagen products like ReefPods to our customers from the beginning."

Copepod Starter Cultures for the Public

Erik started AlgaGen in 2002 with the purpose of using microalgae to produce hi-value products for human and animal health, as well as for biomedical purposes. Erik began working with Andrew Rhyne at the Florida Institute of Technology, and it was Andrew who recognized that producing microalgae could lead to the production of copepods. “There were a number of vendors producing copepods,” he acknowledges, “but no one was offering a collection of starter cultures to the public.”

Enter AlaGen.

Today AlgaGen works with Andrew Rhyne (Roger Williams University), Dr. Adelaide Rhodes (Essential Live Feeds) and Dr. Cortney Ohs (University of Florida) to offer an extensive production-oriented collection of copepods to anyone interested in using them to raise fish. Why so much effort on copepods? “As bizarre as it seems to me,” says Erik, “cutting edge fish production could be centered around the proper nutrition that could come from copepods.”

Wow! But How?

Okay…so most marine aquarists have heard of copepods and some may have even bought them and poured them into their tank because they….well…they do something good, right? But what are copepods really? And, perhaps more importantly, what do they do?

In short, copepods are a small crustacean, and there are seven orders of them (calanoida, harpacticoida, cyclopoida, misophrioida, monstrilloida, siphonostomotoida, and poecilostomatoida). Aquarists are interested in the copepods that are useful, non-detrimental food sources. With Erik’s help, let’s cover the basics and touch on how to use the right copepods in your tropical marine aquarium.

Calanoids

Calanoids (the nauplii pictured here is a baby copepod from the calanoids) are pelagic copepods—they spend their entire life cycle in the water column—and they are an essential food source for any marine organism that feeds in the water column including fish, larval fish and coral. “These copepods eat microalgae,” explains Erik, “and they concentrate the fatty acids from the microalgae in their bodies.” In short, when marine organisms eat the copepods, they obtain the essential fatty acids concentrated in the copepods. This is the number one reason why feeding these copepods to marine ornamental fishes is highly recommended.

In addition to being nutrient rich, these copepods display, what Erik refers to as “a very spastic movement,” which may well trigger a more enthusiastic feeding response. “When I drop calanoids into my tank,” Erik says, “the anthias feed with real vigor.”

While the calanoids are great food items, they do not survive for long. “Life cycles can typically be 20-30 days,” says Erik. “The calanoid will either release eggs or brood them and release live nauplii that will go through several molts to become juveniles then adults.”

Harpacticoids

Harpacticoids (e.g., Tigriopus and Tisbe like the one pictured at the top of this entry) are, unlike calanoids, benthic copepods. “They like substrate and will feed on microalgae, detritus or other copepods,” explains Erik. “Tigriopus is carnivorous; Tisbe is a detritivore, and both are cannibalistic. They will also eat fish flake food and microalgae.” These are the "ReefPods" sold at Saltwaterfish.com (and, by the way, they are on special right now! Buy one get one free!).

These are the copepods aquarists have probably seen on their live rock, and they are the ones most commonly sold. “They can handle harsh conditions such as being stored in a bag or bottle for weeks, and they can survive in a reef tank,” adds Erik. Harpacticoids make great food items for seahorses, mandarins (which, at the time of publication, are on special) and wrasses. They can and should be added repeatedly to ones' tank, and, depending on how the tank is stocked, these copepods can easily be “grazed back” to a minimal population fairly quickly.

Other Copepod Groups

The cyclopoid, monstilloid, siphonostomatoid, poecilostomatoid groups of copepods are not as good as a live food source as these groups contain the commensal and parasitic copepods.

Husbandry How-To

Okay, so now that we know which copepods to use, how should we incorporate copepods into our regular husbandry practices? It’s simple, says Erik.

“They can be added to an aquarium as often as one wants. If there is a refugium as part of the set-up, copepods can be added to the refugium. They should reproduce there without being grazed as long as there is food. Copepods growing in the sump or refugium are potentially introduced into the top tank by the return pump. They can also be added directly into the top tank. The safe way to add them is without the skimmer on but it is not necessary to turn it off. Some people add them during the dark cycle when fish are not about.”

In terms of food for copepods, AlgaGen offers microalgae starter cultures for aquaculturists, researchers and hobbyists.

Bottom Line for Copepod Use in the Saltwater Aquarium

What’s the bottom line? “Whether they are THE food source or one of THE critical food items,” says Erik. “the use of copepods in fin-fish production has demonstrated greater survivals and lower deformities for specific species. Copepods may be critical to raising species of ornamentals that cannot be raised on rotifers or brine shrimp.”

While some argue that its husbandry, not a specific food item, that has led to success with certain species that appear to do well with copepods, there is little doubt that employing copepods as part of your regular husbandry practices is a very, very good idea.

A special "thank you" to Erik at AlgaGen for the images above.

Comments

[Ret]

Dr. Rhodes, The photograph, which was provided to me by one of the people I interviewed for this entry (with appropriate permissions filed), has been removed. Thank you.

[Adelaide Rhodes, Ph.D.]

Hello Ret - I sent you an email about the last photo in this article. Please respond about correctly crediting this photo taken by me in 2000.

Good article by the way. However, just a note that I have been providing copepod starter cultures since 2000. Reef Pods is just one of many products available right now.

Adelaide Rhodes, Ph.D.

[Ret]

Frank, Thanks for the comment. What else would you like to see me write on in the coming weeks?

Ret

[Frank B]

A really interesting post, I especially liked your information regarding the use of Copepods in the saltwater aquarium results in greater survivals and lower deformities for specific species.

The fact that copepods may be critical for certain ornamentals that cannot be raised on rotifers or brine shrimp will be very useful information when passed on to my clients.

Thank you very much for such an informative post.