NPS (Non-Photosynthetic)

About NPS (Non-Photosynthetic)

Non-Photosynthetic Corals (NPS) are a broad group of corals that lack symbiotic zooxanthellae and obtain nutrition by capturing zooplankton and organic particles with their polyps. In nature, they thrive in deep-water habitats, cave systems, and shaded vertical reef walls where sunlight rarely penetrates, often forming dense colonies on overhangs. The group spans diverse families—including sun corals, sea fans, and carnation corals—and is celebrated for its vivid hues of red, orange, yellow, and white. In the aquarium, their low light requirements make them appealing for systems where energy efficiency is a priority, and their sculptural forms add remarkable depth to rockwork layouts. However, successful NPS keeping demands daily targeted feeding and diligent water quality management, placing them firmly in the intermediate-to-advanced category of reef husbandry.

7 things to know before welcoming a NPS (Non-Photosynthetic)

1. 1No Intense Lighting Needed

   NPS corals do not photosynthesize, so high-intensity metal halide or LED lighting is not required. However, they do not thrive in complete darkness either; low, ambient lighting similar to natural shade suits them best. While lighting costs are lower, plan for the increased cost of regular feeding instead.

2. 2Daily Feeding Is Essential

   The defining characteristic of NPS corals is their need for frequent, consistent feeding to survive. Frozen copepods, rotifers, and liquid plankton foods should be offered one to several times daily. Neglecting feedings leads to rapid decline, so this group is not well-suited for hobbyists who travel frequently or have irregular schedules.

3. 3Strong, Varied Flow Required

   NPS corals extend their polyps to capture plankton, requiring moderately strong and varied water flow. A single unidirectional strong current can cause polyps to retract, so using multiple pumps to create turbulence is more effective. Replicating natural, wave-like flow significantly improves feeding efficiency.

4. 4Sensitive to Water Quality

   Frequent feeding easily degrades water quality, making nitrate and phosphate management especially critical. Enhancing protein skimming and performing regular water changes (approximately 10–20% weekly) are key to long-term success. Maintaining a stable temperature of 24–26°C and a specific gravity around 1.025 is also fundamental.

5. 5Placement Matters Greatly

   Placing NPS corals under overhangs or in shaded, cave-like spots within the aquascape best replicates their natural habitat. Direct intense light can damage their tissue. Within the tank, keep them away from other corals to avoid contact and potential stinging from sweeper tentacles.

6. 6Higher Initial and Running Costs

   NPS corals are less commonly available in the hobby, and quality specimens can cost several thousand to tens of thousands of yen per polyp. Equipment such as specialized feeding foods, protein skimmers, and flow pumps also add to the investment. Running costs tend to be higher than for photosynthetic corals, so budget planning is important before you begin.

7. 7Best Suited for Experienced Keepers

   NPS corals are considered an advanced category, and beginners to marine aquariums may find them challenging to keep successfully. It is recommended to first gain experience with live rock and hardier soft corals, building solid water management and feeding routines before attempting NPS. Once a stable environment is established, they can be enjoyed for many years with their unique and striking beauty.

Frequently asked questions about NPS (Non-Photosynthetic)

Q.Can NPS corals be kept without aquarium lighting?

A.Since NPS corals do not photosynthesize, intense lighting is not required. However, some ambient light is still useful for algae control and for managing other tank inhabitants. Keeping them in complete darkness makes overall tank management difficult and is generally not recommended.

Q.How often and how much should I feed NPS corals?

A.Frequency varies by species, but daily to 3–4 times per week is a common guideline. Use target feeding with a pipette when polyps are open, offering small amounts at a time. Overfeeding degrades water quality, so adjust quantities to ensure no significant leftovers remain.

Q.Can NPS corals be kept with other corals and fish?

A.NPS corals are generally non-aggressive and compatible with most tank mates. However, fish that nip at polyps—such as butterflyfish—should be avoided. During feeding, take care that other inhabitants do not steal food before the coral can consume it.

Q.Why are my NPS coral polyps not opening?

A.Common causes include deteriorating water quality (elevated nitrates or phosphates), inappropriate flow, transport stress, or insufficient feeding. Start by testing your water parameters, then reassess flow direction and placement. Allow 1–2 weeks of acclimation after transport before expecting polyps to open consistently.

Q.Are NPS corals suitable for beginner reef keepers?

A.NPS corals generally require daily feeding routines and stable water chemistry, making prior experience with saltwater fish or photosynthetic corals advisable before attempting them. That said, difficulty varies significantly across species, and some are more forgiving than others. Starting with well-documented, hardier species is the recommended approach for those new to NPS keeping.

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