Pearlscale Butterflyfish

The Pearlscale Butterflyfish, Chaetodon xanthurus, is an elegant marine aquarium fish recognized by its pearly white body and intricate crosshatch pattern created by dark-edged scales. A bold black eye stripe and dark forehead marking contrast beautifully with the warm orange-yellow coloration across the rear body, dorsal and anal fins, and tail. This detailed patterning gives the species a refined appearance that stands out especially well in spacious saltwater displays.

Native to the Western Pacific, the Pearlscale Butterflyfish occurs from Indonesia and the Philippines north to the Ryukyu Islands of southern Japan. It inhabits clear coastal reefs, outer reef slopes, and drop-offs, frequently around branching coral habitat. In nature, individuals are commonly encountered singly or in pairs while browsing reef surfaces for small benthic invertebrates, algae, and other available foods.

Reaching approximately 5.5–6 inches as an adult, this butterflyfish is well suited to a mature fish-only or fish-only-with-live-rock aquarium with ample swimming room. Its generally peaceful temperament and manageable adult size make it an appealing choice for butterflyfish enthusiasts, although its tendency to investigate and consume sessile invertebrates makes it unsuitable for aquarists seeking dependable reef compatibility.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 75 gallons
Temperament: Peaceful
Diet: Omnivore
Reef Safe: No
Region: Western Pacific – Indonesia, Philippines, and Ryukyu Islands
Scientific Name: Chaetodon xanthurus

Tank Requirements

Provide a mature marine aquarium with a balanced combination of established rockwork and open swimming space. Caves, overhangs, and sheltered passages give the fish secure retreats, while open areas allow the continuous cruising behavior typical of butterflyfish.

Established live rock is particularly beneficial because the Pearlscale Butterflyfish naturally spends considerable time inspecting reef surfaces for food. Avoid an excessively dense aquascape that limits swimming room, but provide enough structure for the fish to retreat if startled or intimidated.

Moderate water movement, strong oxygenation, efficient filtration, and consistently stable water quality are recommended. A mature system is preferable to a newly established aquarium, especially for newly introduced specimens that may initially rely heavily on natural browsing opportunities.

A secure aquarium cover is advisable during acclimation and whenever the fish is housed with more active tankmates.

Diet and Feeding

The Pearlscale Butterflyfish is an omnivorous browser that naturally feeds on small benthic invertebrates, algae, and other edible material found across reef surfaces.

In captivity, offer a varied diet including mysis shrimp, enriched brine shrimp, finely chopped shrimp, clam, mussel, krill, and quality frozen marine blends. Butterflyfish preparations containing marine invertebrate ingredients can also provide useful nutritional variety.

Supplement meaty foods with spirulina-based preparations, marine algae, and high-quality omnivore pellets or flakes once the fish is accepting prepared foods consistently.

Newly introduced specimens may respond especially well to clam or mussel presented on the shell or other foods positioned close to rockwork. Feed two to three smaller meals each day when practical.

Temperament and Tankmates

The Pearlscale Butterflyfish is generally peaceful toward unrelated marine fish and can coexist with many appropriately sized community species. Good tankmates include tangs, rabbitfish, peaceful wrasses, clownfish, gobies, and other non-aggressive marine fish.

Territorial behavior may occur toward other butterflyfish, particularly closely related or similarly patterned species. A single specimen is the simplest arrangement for most aquariums.

Pairs occur naturally, and a compatible pair may be maintained in a sufficiently spacious system. Two unrelated specimens should not automatically be expected to pair peacefully, particularly once established territories have formed.

Avoid highly aggressive or excessively competitive tankmates that may intimidate the butterflyfish or prevent it from feeding adequately.

Reef Compatibility

The Pearlscale Butterflyfish is not considered reliably reef safe. Although its natural diet includes algae and small benthic invertebrates, captive specimens may nip at soft corals, stony coral polyps, gorgonians, zoanthids, tubeworms, and other sessile reef organisms.

Clam mantles and small ornamental invertebrates may also be investigated. Individual behavior varies, but generous feeding does not guarantee that a specimen will ignore corals.

For predictable long-term husbandry, this species is best maintained in a fish-only or fish-only-with-live-rock aquarium rather than a reef display where protecting corals and sessile invertebrates is a priority.

Water Parameters

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

Stable salinity, strong oxygenation, and consistently clean water are more important than attempting to maintain an exact value within these ranges.

Common Considerations

• Not reliably reef safe: Corals, tubeworms, clam mantles, and other sessile invertebrates may be nipped or consumed.

• Mature rockwork is beneficial: Established reef surfaces provide natural browsing opportunities and help newly introduced fish acclimate.

• Frequent varied feeding: Offering several small meals of marine-based foods helps maintain body condition.

• Butterflyfish territoriality: Use caution when combining it with other butterflyfish, particularly similar species.

• Peaceful surroundings preferred: Aggressive tankmates can cause stress and may interfere with feeding.