Six-Line Wrasse

Overview

General Description: A vivid, active reef wrasse with six orange stripes over a blue-purple body. It is hardy, compact, and an energetic rockwork hunter, but its reputation as a simple pest-control fish often overlooks serious territorial aggression.

Appearance: A blue to violet body crossed by six narrow orange horizontal lines, red eyes marked with pale stripes, a greenish tail, blue fin accents, and a small dark eyespot near the upper tail base.

Personality: Inquisitive, fast, secretive at first, and increasingly bold. It constantly investigates crevices and may patrol the entire aquarium as its territory.

Notable Characteristics: Sleeps inside a rock crevice, often within a mucus cocoon, and hunts tiny crustaceans and other invertebrates throughout the day.

General Suitability: Best for a mature reef with dense rockwork, a tight lid, robust tank mates, and a stocking plan that adds the Six-Line late rather than allowing it to dominate timid newcomers.

Natural Habitat

Native Distribution: Red Sea and eastern Africa across the Indian and Pacific Oceans to the Tuamotu Islands, north to the Ryukyu Islands and south to Lord Howe and Austral Islands

Ocean/Region: Tropical Indo-Pacific

Depth: Approximately 2-35 m (7-115 ft), commonly shallower than about 20 m

Reef Zone/Habitat: Clear coastal reefs, shallow reef crests, seaward slopes, branching coral thickets, rubble, caves, and crevices

Natural Water Movement: Moderate to strong around reef crests and outer slopes, with protected spaces inside coral branches

Natural Behavior: A shy, diurnal micro-predator that stays close to complex coral shelter, searches surfaces for small crustaceans, and may occur in loose groups in the wild.

Other Habitat Notes: Dense three-dimensional cover is central to its security and feeding. At night it wedges into a cavity and may secrete a mucus sleeping cocoon.

Aquarium Setup

Minimum Tank Size: 30 gallons for one; 40 gallons or larger is preferable for a community and more defensible territories

Preferred Tank Dimensions: A long tank with extensive horizontal rockwork and broken sight lines is better than a tall, open aquarium

Rockwork: Provide abundant mature rock with narrow caves, branching structures, tunnels, and shaded passages

Hiding Places: Several secure crevices are essential for acclimation and sleeping

Open Swimming Space: Leave open lanes around and above the rockwork while maintaining immediate access to cover

Substrate: Sand or aragonite is suitable, but this species normally sleeps in rockwork rather than burying in sand

Water Flow: Moderate with good oxygenation and lower-flow pockets among rocks

Lighting: Standard reef lighting with shaded retreats and a gradual transition to darkness

Lid Requirement: Essential. Six-Line Wrasses are agile jumpers and can escape through small gaps.

Special Setup Requirements: Use a tight mesh lid, guard overflow openings, create broken sight lines, and ideally add the wrasse after peaceful community fish are established.

Water Parameters

Temperature: 75-82°F (24-28°C)

Specific Gravity/Salinity: 1.023-1.026 (approximately 32-35 ppt)

pH: 8.1-8.4

Alkalinity: 7-11 dKH, kept stable

Other Relevant Parameters: Ammonia 0 ppm; nitrite 0 ppm; maintain controlled nitrate, strong gas exchange, and stable reef chemistry

Water Quality Sensitivity: Hardy after acclimation but vulnerable to ammonia, low oxygen, abrupt salinity changes, and shipping stress

Stability Requirements: Maintain consistent temperature, salinity, pH, alkalinity, and oxygenation. Acclimate carefully and avoid sudden corrections.

Behavior & Social Needs

General Behavior: Constantly patrols rock faces and crevices for tiny prey, darts rapidly between shelters, and becomes more visible and confident after settling

Aggression: Can be substantially more aggressive than its small size suggests, chasing timid fish, new additions, and similar wrasses

Territorial Behavior: Moderate to high once established; the fish may treat most rockwork as its territory

Activity Level: High and diurnal

Swimming Level: All levels near rockwork, primarily lower and middle zones

Group Requirements: Keep one per aquarium in most home systems. Wild loose grouping does not translate reliably to aquarium compatibility.

Pairing: Pairs are difficult to obtain and are not recommended for typical community aquariums because sexing is unreliable and aggression may occur

Other Notable Behaviors: Sleeping in a crevice, producing a mucus cocoon, weaving tightly through rock, and briefly hiding when startled are normal.

Reef Compatibility

Reef Safe: Generally yes

Coral Compatibility: Does not normally eat or damage corals

Invertebrate Compatibility: Use caution with very small shrimp, feather dusters, worms, amphipods, copepods, tiny snails, and other bite-sized invertebrates

Potential Risks: May reduce desirable microfauna, eat small ornamental crustaceans, harass peaceful fish, and jump from an uncovered tank

Conditions Affecting Compatibility: Predation risk rises with smaller invertebrates and limited feeding; aggression increases with cramped territory, similar fish, and new additions introduced after the wrasse.

Tank Mates

Good Tank Mates: Established Ocellaris Clownfish, Royal Gramma, larger cardinalfish, sturdy gobies, moderately assertive reef-safe fish, and larger ornamental shrimp

Use Caution With: Common Firefish, timid gobies, Tailspot Blenny, flasher and fairy wrasses, dragonets, small peaceful cardinalfish, and any fish added after the Six-Line

Avoid: Other Pseudocheilinus wrasses, very timid or delicate fish, tiny ornamental shrimp, slow feeders vulnerable to harassment, and large predators

Same-Species Compatibility: Usually poor in home aquariums. Keep singly unless using a large specialized system with a verified pair and separation options.

Same-Genus Compatibility: Avoid mixing with Four-Line, Mystery, Eight-Line, or other Pseudocheilinus wrasses because territorial conflict can be severe

Compatibility Notes: Add the Six-Line late, rearrange some rockwork before introduction if necessary, use an acclimation box, and have a realistic removal plan if persistent bullying begins.

Diet & Feeding

Natural Diet: Small benthic crustaceans and other tiny reef invertebrates picked from coral and rock surfaces

Captive Diet: A varied carnivorous marine diet supplemented by natural hunting on mature rock

Recommended Foods: Mysis shrimp, enriched brine shrimp, copepods, calanus, finely chopped krill or seafood, small marine pellets, and quality frozen carnivore blends

Feeding Frequency: One or two small meals daily; juveniles and thin newcomers may benefit from additional small feedings

Feeding Behavior: Fast, active, and competitive. It captures food in the water column and continuously searches rockwork between meals.

Special Nutritional Requirements: Use small, varied marine proteins and do not rely on pests or pods as the sole diet. Ensure timid tank mates still receive food.

Sexing & Breeding

Male/Female Differences: Sexing is unreliable by casual inspection. The species is generally understood to be a protogynous hermaphrodite, with a dominant female able to transition to male; males tend to be larger and more intensely colored.

Breeding Difficulty: Advanced; spawning may occur, but pelagic eggs and tiny larvae require specialized culture methods

Reproductive Strategy: Oviparous pair spawning with broadcast pelagic eggs; sequential hermaphroditism is reported for the species

Pair Formation: A dominant male may pair briefly with a female for spawning. Maintaining a stable pair in a home aquarium is difficult because of territorial aggression.

Spawning Behavior: Courtship and spawning typically occur near dusk, when a pair makes a rapid upward rush and releases eggs and sperm into the water column.

Eggs/Larvae: The fertilized eggs are pelagic. Larvae hatch small and require microscopic planktonic foods.

Larval Care: Use a dedicated rearing system with stable water, gentle aeration, appropriate greenwater methods, rotifers or copepod nauplii, and carefully staged enrichment.

Captive Breeding Availability: Very limited; nearly all Six-Line Wrasses in the trade are wild collected.

Health

Common Health Concerns: Marine ich, velvet, flukes, intestinal parasites, bacterial infections, jumping injuries, physical trauma from rockwork, aggression-related fin damage, and transport stress

Parasite Susceptibility: Can contract common marine parasites, though wrasses may not always show obvious external spots early

Disease Susceptibility: Generally hardy, but rapid breathing, appetite changes, and unusual hiding should be investigated promptly

Signs of Stress: Rapid breathing, white spots or fine dusting, clamped or torn fins, cloudy eyes, faded color, persistent hiding, frantic pacing, jumping attempts, or loss of appetite

Quarantine Considerations: Use a tightly covered quarantine tank with multiple PVC elbows or rock-like inert shelters. Observe skin, respiration, feces, and feeding; research medication tolerance before treatment.

Common Keeper Mistakes: Buying it only for pest control, underestimating aggression, adding it before timid fish, mixing it with similar wrasses, using an open lid, and assuming rock-sleeping means it needs a sand bed

Special Sensitivities: Handling stress, jumping, insufficient hiding places, bullying or being bullied, low oxygen, abrupt parameter changes, and inappropriate medication dosing

Beginner Suitability

Beginner Friendly: With caution

Why: It is hardy, colorful, reef safe with corals, and usually eats prepared foods, but aggression can destabilize an otherwise peaceful community

Major Challenges: Managing territorial behavior, choosing robust tank mates, adding fish in the right order, preventing escapes, and capturing the wrasse if removal becomes necessary

Before You Buy

Important Considerations: Choose an alert fish with clear eyes, intact fins, a full body, normal breathing, and a demonstrated feeding response. Confirm that the tank has a tight lid, dense rockwork, and no timid planned additions that the wrasse may later harass.

Adult Size: Up to about 4 inches (10 cm)

Aggression: Semi-aggressive to aggressive despite its small adult size

Reef Compatibility: Coral safe, but not completely safe with small invertebrates or desirable microfauna

Dietary Requirements: Carnivorous micro-predator requiring varied small meaty marine foods

Long-Term Requirements: A covered 30-gallon-or-larger mature aquarium, preferably 40 gallons or more for a community, with complex rockwork, compatible tank mates, and consistent feeding for approximately 4-6 years

Species-Specific Information

Anything important that does not fit above: The Six-Line Wrasse is frequently recommended for small reefs because it stays compact, but physical size is not a reliable guide to social impact. A mature individual can dominate a much larger community, especially when added early. The Pink-Streaked Wrasse and small Possum Wrasses are often better choices when a similarly sized but gentler wrasse is desired.