Photosynthetic corals dominate natural, shallow tropical coral reefs. So it shouldn’t come as much of a surprise that they are so prevalent in the reef aquarium hobby. But as some aquarists master the husbandry of more delicate/demanding stony corals types, and successfully keep them for long periods of time, they start to look to other challenges. One such alternative for these more ambitious hobbyists is an NPS aquarium.
NPS (non-photosynthetic) corals are quite a bit different from their zooxanthellate counterparts. They certainly look different. In fact, even for moderately experienced hobbyists, they’re pretty easy to distinguish with a mere glance. But they differ most significantly in their diets and favored habitats.
NPS corals, as a group, are made up mostly of soft corals (including sea fans and sea whips), whereas photosynthetic species are more often stony. But perhaps the most notable characteristic of NPS aquaria isn’t the types of corals they typically hold, but the very fact that they hold so many non-coral sessile inverts. These systems can exhibit a truly impressive diversity and richness of lifeforms, ranging from soft and stony corals to sponges, tunicates, scallops, barnacles, tube worms, tube anemones, and so on.
For aquarists, the one big thing NPS creatures have in common is that they lack zooxanthellae–and therefore must be fed. Many of their feeds are best offered live. This is the aspect of NPS aquarium keeping that the uninitiated find most intimidating. After all, the obligate filter-feeders kept in these tanks must eat a lot and their foods usually must be of a specific type and/or size. An especially frustrating part about feeding plankton is that you can’t actually see the animals eating it. How can you know that they’re eating anything at all?
Heaping it on
Generally, you’ll need to feed a wide array of foods to meet the varied demands of the varied livestock in most NPS systems. This menu includes nutritionally enriched particulate organic matter (POM) as well as various planktonic food sources. Since filter-feeders can be surprisingly selective about foods and even food particle size, and have rather high nutritional demands, it is best to offer the widest variety and highest quality of foods possible.
We here recommend a handful of items that are extremely useful for nourishing NPS aquarium animals.
Benereef. Made with a blend of nutritious food items, including phytoplankton and live probiotics, this is an excellent prepared food for your NPS reef inhabitants. With a 3-3,000 micron particle-size, Benereef accommodates a broad range of filter-feeders. It easily may be either broadcast fed or target fed! Highly regarded throughout the reef aquarium hobby, this diet is proven to increase feeding response, coloration, growth and regeneration of stressed corals.
Ultimate Ecopack. This comprehensive combo includes select items that form the entire base of the marine food pyramid: Live probiotic bacterioplankton, a blend of live phytoplankton, a blend of live copepods and enriched marine snow. This premium package is nutritionally complete and provides the full range of food particle sizes. While suitable for all types marine aquaria, the Ultimate Ecopack is practically indispensable for NPS systems!
Daphnia magna. Larger polyped stony NPS corals (sun corals, cups corals, etc.), tube anemones and other such predators require a meatier type of zooplankton. While items such as enriched adult brine shrimp are suitable as a base diet for these creatures, a more varied diet that includes supplemental feeding of larger live zooplankton such as Daphnia magna significantly improves health and rate of growth.
Dragon Roe. For NPS corals that are not equipped to capture particles as small as phytoplankton, the fresh fish eggs in Dragon Roe are a critical source of Omega 3 polyunsaturated fatty acids (EPA and DHA). Additionally, fish eggs (a valuable food on wild reefs) are rich in protein. Many, many corals (and small finicky fish such as mandarins) eagerly accept this natural delicacy.
Once considered difficult, we now culture zooxanthellate corals routinely–not just in labs and seaside “farms” but also in garages and basements across the globe. All that was necessary to keep and even propagate these “delicate” animals was some understanding of their environmental and nutritional needs. Same probably goes for the NPS corals.
Yes, zooxanthellate inverts certainly dominate reefs in terms of sheer abundance. But considering the diversity of azooxanthellate inverts (from sponges to crinoids) that is typically also present there, it would seem that all sorts of cool critters are grossly underrepresented in the vast majority of aquaria. Why would we ignore this amazing fauna?
Many of these species indeed have dismally poor records of captive survivability. But are they truly “difficult” to maintain, or have we simply failed–over and over again throughout the past–to feed them properly? No doubt, the key to success here is feeding the right foods. But then there is the challenge of feeding them enough. And if we feed them enough, which is a lot, we face the increasingly difficult task of maintaining acceptable (if not excellent) water conditions.
Perhaps advances in both aquarium nutrition and aquarium filtration have finally presented us with a real chance of successfully displaying these gorgeous creatures in the home aquarium. Developments in the use of probiotic bacteria—microbes that simultaneous serve as a food source and help to maintain good water quality—may push us further along in this pursuit. From the looks of things, we’re much, much closer to the day when the average hobbyist can build a truly complete and realistic representation of coral reef ecosystems.