Copepods are Nature’s trophic intermediaries. That is, they transfer nutrients and food energy from lower (e.g. plants) to higher (e.g. carnivores) levels in the food chain. This also happens to make them nearly indispensable in aquarium systems, where they (1) consume unwanted material such as nuisance algae and detritus and (2) are eaten by zooplanktivores ranging from fish (anthias, mandarins, etc.) to corals. Their young, quite notably, generally are phytoplanktivores, eating free-living microalgae from the water column during their planktonic larval stages.
As it is comparatively more nutritious, pods prefer algal material to detritus. They mainly consume soft microalgae. This means that they typically do not eat crustose forms such as coralline algae, nor do they eat macroalgae (aside from dead, decaying, softened material). They love green algae and diatoms; these are both available in a benthic form as thin films (for adult harpacticoid copepods) and in a planktonic form as single cells (for larval harpacticoid copepods and all cyclopoid copepods). As such, a diverse community of copepods helps to keep the aquarium water clear and the rocks, sand, and glass free of green or brown films.
Being so beneficial, aquarists generally seek to culture as high of numbers of these critters as possible. Unsurprisingly, their population densities are limited by food availability. This means that if you add pods to remedy a preexisting algae plague or detritus pool, you might observe steady increases during the exponential growth phase, only to see numbers drop as food supplies are gradually depleted.
Sometimes a pod population will decline before the nuisance algae and/or detritus is gone, or worse yet, they never really take off at all. Where losses to heavy mechanical filtration (e.g. filter socks) or
UV sterilization can be discounted, this usually due to the starvation of larvae. Remember, their “babies” need phyto! Those aquarists who dose phyto on a regular basis maintain larger pod populations (can’t have lots of adults without lots of larvae). And, when raised on a nutritionally balanced live phyto product such as OceanMagik, your pods will be more nutritious for the animals that prey on them!
What Do You Feed Copepods in a Refugium?
Copepods are good. The more, the better. That’s why you want to produce as many as possible. And as fast as you culture them, your corals and small reef fish will eat them! For sure, due to the heavy predation that typically occurs in a reef tank (a ...
Are Copepods a Good Sign?
Copepods are widely believed to constitute over 75% of the biomass of all zooplankton on Earth. They may be found in nearly every marine and freshwater habitat from coral reefs to roadside ditches. But it is not just their omnipresence that makes ...
Amphipods Are Not Copepods
There is hardly a more natural way to feed your aquarium animals, or to clean your tank, than with microcrustaceans. It's pretty safe to say that these little creatures, frequently referred to as "pods," have indeed revolutionized saltwater aquarium ...
Do Copepods Need Light?
Let’s start by making one thing clear: There are no animals that “need” light in the way that photosynthetic organisms do. Only plants and certain microbes are capable of performing photosynthesis (“photosynthetic” corals and clams, don’t need light, ...
Will Shrimp Eat Copepods?
Copepods have almost become a staple of the marine aquarium systems, serving as (1) algivorous and detritivorous members of the clean-up crew and (2) providing a self-supplying, nutritious live food source for the most finicky corals and small reef ...