The reef aquarium hobby continues to reach new heights. This is most evident by the extraordinarily beautiful systems we see on display in public places, in images on social media, in advertisements, and even in some homes. These advancements have come about not only through improved technologies and supplements, but also through a better understanding of how natural marine ecosystems function.
Undoubtedly, the surest way to build a naturalistic aquarium system is through the feeding of live plankton. Of all the zooplanktons one might find in the aquarium trade—and indeed in the wild—copepods are of greatest importance. The tiny, planktonic juvenile copepods are a particularly healthful food source for corals and other filter-feeding invertebrates.
Harpacticoid copepods are especially useful to reefkeepers. One reason for this is that these copepods are benthic (i.e. bottom-dwelling) as adults. The adults make great targets (and an extremely nutritious meal) for many species of small reef fishes. They might even be preyed on by other “pods” such as amphipods. The larger its adult size is, the more species can locate, capture and consume it.
The Supreme Pod
It should be enough that copepods are magnificent live aquarium foods. Even so, they can benefit a reef tank in yet other ways. Most notably, harpacticoids consume detritus and microalgal films that appear on the rocks, glass, etc. In this way they transfer nutrients from wastes back to hungry aquarium livestock. Some of those individuals that escape predation will mate, producing planktonic larvae. These larvae graze phytoplankton (i.e. suspended, single-cellular algae) from the water column. Some of these young will be consumed by zooplanktivorous invertebrates; some will eventually settle onto the bottom and complete development as adults.
And then? You guessed it; under the right conditions, these individuals will reproduce, supplying the captive ecosystem with a new generation. A propagative population of pods can play a long-term role in nutrient cycling (not to mention make an aquarist’s maintenance routine simpler).
There are a handful of copepod species to choose from. Each is best suited to a particular purpose. This is why mixed species products are ideal. But the very best candidate for reef aquaria bears certain characteristics:
- It is hardy enough to survive under typical aquarium conditions.
- It has a benthic adult form.
- It has a large adult size.
- It is nutritious and rich in color-enhancing pigments
For the reason that it fits all of these criteria, the harpacticoid Tigriopus californicus remains extremely popular among reef aquarium hobbyists.
One Tough Pod
californicus is adapted to the highly unstable, and sometimes inhospitable, conditions of the high shore (e.g. tidepools). In fact, they have a thermal tolerance range that few higher animals can match. Specifically, we’re talking about water temperatures from less than 50°F (10°C) to over 104°F (40°C).
Thus, they feel right at home in the relatively cozy conditions of a reef aquarium. There they will feast greedily upon film algae and solid organic wastes. They will be considerably more productive where a properly sized refugium has been installed; if the refugium contains some rubble rock or MarinePure cubes to crawl on, even better. There they can hide, rest, forage and find mates. Predator-free populations can reach densities as high as 20,000 individuals per liter.
Biggest little pods
californicus is certainly among the largest of the copepod species typically offered to marine aquarists. It has a size range of 116 microns to 1.2 millimeters or more. Whoppers as big as three millimeters have been reported. But adults average out at around one millimeter.
Sure, that might not sound very big in comparison to most other aquarium animals. But that’s huge for a harpacticoid copepod. Furthermore, a span of a-hundred-and-something microns to a millimeter is a huge range of size. While its nauplii are small enough to be consumed by the finest filter-feeding invertebrates, its fully mature adults are large enough to be seen, caught and eaten by a fairly wide variety of fishes—from mandarins to pygmy angelfish to six-lined wrasses. This makes them invaluable as an all-purpose pod for even the most highly diverse reef aquarium system.
A wholesome treat
T. californicus is, like most other harpacticoids, highly nutritious. It is rich in lipids and fatty acids. It has a high protein content. And one more thing: It’s really, really red. While so many other pods are more-or-less translucent, T. californicus has a distinctive ruddy hue. This is due primarily to carotenoid pigments. These colorants are derived from bacterial/plant pigments that are present in pod’s food. However, by getting eaten itself, the pod can serve as an intermediary for the passage of carotenoids up the food chain. So yes, if your fish are eating Tigriopus (and the pod larvae have a rich source of phytoplankton and bacterioplankton to exploit), there’s a good chance that they will exhibit intense coloration.
Sludge-eating bacteria are highly recommended here. Of these, purple non-sulfur bacteria (e.g. PNS Probio™) are an excellent choice, as they are especially rich in important carotenoids such as astaxanthin. By nutritionally enriching the detritus, these bacteria make tiny detritivores such your Tig Pods more nutritious to pod-eaters like mandarins!
Best with the rest
Tigriopus really could be the ultimate marine aquarium pod. That being said, it is always better to build the most diverse community of clean-up crew species as possible. That is why mixed species products are ideal. But any bag of mixed pod species should include Tigriopus. And, to best capitalize on this species’ broad size range, the choicest product will include individuals of all life stages.
A sound way to seed Tigriopus into your aquarium is with the Tig Pods and OceanMagik combo. Tig Pods contains individuals from every life stage. The inclusion of OceanMagik (composed of four select phytoplankton species) gives the young pods a major lift. Even better is 5280 Pods, a mixed-species live product that includes Tigriopus as well as Tisbe and Apocyclops. 5280 Pods is also available in a combo with OceanMagik. These high-quality live aquarium foods can be delivered to the reefkeeper’s front door. In fact, automatic shipments can be sent each month through a subscription.
Best of all? AlgaeBarn’s Ultimate Refugium Starter Pack has everything one would need to properly set up, seed and establish a refugium. Each pack (which is available in a number of sizes) includes a bag of 5280 Pods, Turbo Start nitrifying bacteria, MarinePure cubes, OceanMagik phytoplankton and a starter patch of CleanMacro seaweed. There’s hardly a better way to put pods in your reef.