Midnight (Nox) Dwarf Angelfish

The Midnight (Nox) Dwarf Angelfish, Centropyge nox, is a striking saltwater fish distinguished by its nearly uniform jet-black to deep charcoal coloration. Subtle blue highlights may appear around the face and fin margins under strong reef lighting, while the dark body creates a dramatic contrast against brightly colored corals and other marine fish. Its simple yet bold appearance makes it one of the most distinctive dwarf angelfish for established saltwater aquariums.

Native to the Western Pacific, this species occurs from the Ryukyu Islands and Indonesia through the Solomon Islands, Great Barrier Reef, New Caledonia, Palau, and portions of Micronesia. It naturally inhabits coral-rich outer reef slopes, lagoons, and passages where abundant rockwork and invertebrate growth provide shelter and grazing opportunities. With an adult size of approximately 4 inches, the Nox Angelfish combines manageable dimensions with the active, inquisitive behavior typical of Centropyge angelfish, making it well suited to mature fish-only aquariums and carefully planned reef aquariums.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 70 gallons
Temperament: Semi-aggressive
Diet: Omnivore
Reef Safe: With Caution
Region: Western Pacific
Scientific Name: Centropyge nox

Tank Requirements

The Midnight Angelfish should be maintained in an established marine aquarium with abundant live rock, caves, overhangs, and narrow crevices. A 70-gallon or larger aquarium provides adequate territory for its adult size while allowing sufficient room to forage and establish secure hiding areas.

Complex rockwork is especially important for this species. In addition to providing shelter, mature live rock supplies natural algae and biofilm that the fish can graze throughout the day. Leave some open swimming space between rock structures while maintaining multiple escape routes and sheltered areas.

Moderate water movement, good oxygenation, efficient filtration, and stable water quality are ideal. Newly introduced specimens may initially remain close to rockwork but typically become increasingly visible as they acclimate.

Diet and Feeding

The Nox Angelfish naturally consumes algae and associated organic material from reef surfaces. In captivity, it should receive a varied omnivorous diet with a strong vegetable component.

Offer spirulina-based flakes or pellets, marine algae, high-quality angelfish preparations, mysis shrimp, enriched brine shrimp, and balanced frozen marine blends. Mature live rock provides additional grazing opportunities and is particularly beneficial between prepared feedings.

Feed two or more small meals daily while allowing the fish to forage naturally throughout the aquarium. A varied diet helps maintain good body condition and supports normal grazing behavior.

Temperament and Tankmates

The Midnight Angelfish is semi-aggressive and can become territorial after establishing itself in the aquarium. Aggression is most commonly directed toward other dwarf angelfish and similarly shaped fish competing for the same rockwork and feeding areas.

It can coexist with many appropriately sized marine community fish, including clownfish, wrasses, gobies, blennies, cardinalfish, chromis, and larger peaceful to semi-aggressive species.

For most home aquariums, keeping a single Nox Angelfish is the simplest approach. Housing multiple dwarf angelfish requires a considerably larger aquarium, extensive rockwork, and careful species selection.

Reef Compatibility

The Midnight Angelfish is best considered reef safe with caution. Like other dwarf angelfish, individual specimens may nip at sessile invertebrates even when otherwise well fed.

Potential targets include soft coral polyps, zoanthids, fleshy large-polyp stony corals, and clam mantles. Some individuals coexist successfully in reef aquariums for extended periods, while others develop persistent picking behavior.

Ornamental shrimp, snails, crabs, and other mobile reef invertebrates are generally at lower risk. Providing abundant mature rockwork and a varied diet may help redirect natural grazing behavior, but complete coral safety cannot be guaranteed.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Stable conditions are more important than repeatedly adjusting the aquarium to achieve an exact number. Maintain consistent temperature and salinity along with good oxygenation, efficient filtration, and regular aquarium maintenance.

Common Considerations

• Reef safe with caution: Individual fish may nip soft corals, zoanthids, fleshy stony corals, and clam mantles.

• Territorial behavior: Established specimens can become assertive toward other dwarf angelfish and similarly shaped competitors.

• Mature rockwork recommended: Live rock provides both secure hiding places and important natural grazing surfaces.

• Naturally cryptic behavior: Newly introduced specimens may spend considerable time within rockwork before becoming comfortable in open areas.

• Single-specimen housing: Keeping one dwarf angelfish is generally the most predictable approach unless the aquarium is large enough to support multiple territories.