Bartlett's Anthias - Female - Marshall Is.
Bartlett's Anthias - Female - Marshall Is.
Goes well with:
FAQs Answers to the most common questions.
How many Bartlett’s Anthias should I keep together, and what’s the best male-to-female ratio to reduce aggression and sex-changing conflicts?
Bartlett’s Anthias do best in small harems: 1 male with 3–6 females in tanks of 75 gallons or larger. If you start with all females (5–7) in a 75–120 gallon tank, the dominant one will turn male naturally. Avoid more than one established male in tanks under 180 gallons, as they will fight, harass subordinates, and stress the group. If you’re adding a new group to an existing tank, introduce all females at once and add the male last or let the group form its own male; sudden introduction of a mature male to a tank with a developing sub-male is one of the most common triggers for constant chasing and hiding.
Why is my Bartlett’s Anthias turning yellow on the back and losing its purple coloration, and is this a sign of poor health?
Color shift in Bartlett’s is usually hormonal and social, not a health issue. Males show bright yellow dorsally with magenta to purple on the lower body and a more extended dorsal fin. Females are more uniformly pinkish with less intense yellow. When a female begins to transition to male due to social dominance (for example, if the male dies or there is no clear male), you’ll see the yellow spreading along the back, intensified purple on the lower body, and fin changes over several weeks. If the fish is still eating well, swimming confidently in the water column, and you don’t see clamped fins, frayed edges, spots, or rapid breathing, the color change is normal sexual transition, not disease.
My Bartlett’s Anthias spends most of the day hiding under rock ledges instead of schooling in the open. What specific environmental factors cause this behavior?
Constant hiding in Bartlett’s is often due to a combination of three factors: excessive flow, harsh top-down lighting, and lack of midwater cover. Bartlett’s like strong but diffuse flow and will avoid narrow, blasting streams. They also dislike intense, unshaded light; bare, open rockscapes under bright LEDs make them feel exposed. Provide overhangs, caves with open faces, and branching rock structures that create vertical “walls” they can hover beside. Add moderate flow that alternates and breaks around rock, and aim for a shaded-to-bright gradient across the tank. A few peaceful, active midwater fish (such as fairy or flasher wrasses) can help them feel more secure, whereas boisterous tankmates like large tangs or dottybacks will push them into hiding.
What feeding schedule and food types are ideal for maintaining the weight and coloration of Bartlett’s Anthias in a mixed reef tank?
Bartlett’s Anthias have high metabolisms and do best with multiple small feedings daily: 2–4 times a day is ideal. Use a mix of fine meaty foods: enriched frozen mysis, finely chopped krill, small calanus, enriched brine, and quality marine pellets in the 0.5–1 mm range. Add a planktonic component such as frozen cyclops or copepod-based foods to mimic their natural diet of zooplankton. Soak foods periodically in vitamin and HUFA supplements to support immune health and color. In heavy coral tanks, use a high-quality automatic feeder for small pellets to maintain frequent feedings without major nutrient spikes, and balance feeding by increasing export (skimming, refugium, or regular water changes).
Can Bartlett’s Anthias be kept successfully in a nano or small reef tank long-term if I only keep a single fish, and what special care would that require?
A single Bartlett’s Anthias can live in a 40–50 gallon tank, but this is a compromise and not ideal. In small tanks, keep just one specimen to avoid hierarchy stress. Provide high-quality filtration, stable temperatures (76–78°F), and strong but diffused flow. Because they are very active swimmers, ensure at least 3 feet of horizontal swimming space and a tightly covered top—they are prone to jumping when startled. Feed at least twice daily with small meaty items and tiny pellets; in smaller volumes, this requires diligent nutrient management (regular water changes and efficient skimming). Give it visual shelter with rockwork and avoid aggressive tankmates such as large clownfish or dottybacks; peaceful wrasses or small gobies are better companions. While this setup can work, Bartlett’s display their most natural behavior and colors in larger tanks with a small group.
All listed sizes are approximate, not guaranteed, and may vary slightly.
The female Bartlett’s Anthias (Nemanthias bartlettorum, formerly Pseudanthias bartlettorum) is a brilliantly colored saltwater fish featuring a warm lavender-to-pink body contrasted by a broad golden-yellow area across the upper back and tail. Females typically show a larger yellow region than mature males and lack some of the intensified magenta coloration and elongated fin development associated with dominant males. Their bright coloration and constant midwater activity make them especially attractive in illuminated reef aquariums.
This Marshall Islands form originates from the central Pacific portion of the species’ natural range, where Bartlett’s Anthias occur around reef slopes in aggregations composed primarily of females and juveniles with comparatively few males. They spend much of the day swimming above reef structure and capturing small zooplankton carried through the water column.
The female Bartlett’s Anthias is an excellent marine aquarium fish for established reef aquariums and appropriately stocked fish-only systems. Although generally compatible with peaceful community fish, Bartlett’s Anthias establish a social hierarchy among themselves, and females have the ability to transition into males when social conditions favor the change.
Quick Care Guide
Care Level: Moderate
Minimum Tank Size: 70 gallons
Temperament: Semi-aggressive
Diet: Carnivore / Planktivore
Reef Safe: Yes
Region: Marshall Islands – Central Pacific
Scientific Name: Nemanthias bartlettorum
Tank Requirements
Provide a mature marine aquarium with generous open swimming space above and around the rockwork. Bartlett’s Anthias are active water-column swimmers and should not be confined to densely packed aquascapes with limited room to move.
Live rock should provide multiple caves, ledges, and shaded retreats where the fish can shelter at night or escape unwanted attention from tankmates. Numerous retreat areas become especially important when maintaining several anthias together.
Moderate to strong, well-distributed water movement is appropriate and helps replicate the current-swept reef environments where these fish naturally feed. Strong oxygenation and efficient filtration are also beneficial because the frequent feeding required by anthias can increase nutrient input.
A securely fitted mesh screen or aquarium lid is recommended, as anthias may jump when startled or chased.
Diet and Feeding
Bartlett’s Anthias are carnivorous planktivores that naturally feed on zooplankton and small crustaceans suspended in the water column.
Offer a varied captive diet consisting of enriched mysis shrimp, enriched brine shrimp, copepods, frozen plankton, finely chopped marine seafood, quality frozen reef blends, and appropriately sized marine pellets or flakes. Foods that remain suspended in the water column encourage natural feeding behavior.
Two to three small feedings per day are recommended, with additional small meals beneficial when practical. Newly introduced females may respond especially well to copepods, mysis, and other small frozen foods while becoming accustomed to prepared diets.
Temperament and Tankmates
Female Bartlett’s Anthias are generally peaceful toward unrelated community fish but can become assertive with other anthias as a social hierarchy develops. Dominant individuals may chase subordinate females, particularly when aquarium space or hiding areas are limited.
Suitable tankmates include clownfish, gobies, blennies, fairy and flasher wrasses, tangs, peaceful angelfish, and other non-predatory marine fish. Avoid highly aggressive species that may intimidate the anthias or prevent it from feeding regularly.
A single female can be maintained successfully. Groups can also be kept in larger aquariums with ample swimming room and numerous retreats, but social interactions should be monitored carefully. In the absence of a dominant male, one female may begin transitioning into a male. Occasionally, multiple females may begin transitioning, which can result in increased aggression.
Reef Compatibility
The female Bartlett’s Anthias is considered reef safe and is an excellent choice for coral-dominated aquariums. It does not normally consume or damage stony corals, soft corals, clams, or other sessile reef organisms.
It is also generally compatible with ornamental shrimp, crabs, snails, and other common reef invertebrates. Tiny copepods and other planktonic crustaceans may naturally be consumed as part of its normal feeding behavior.
Water Parameters
Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH
Maintain stable, well-oxygenated water with consistently good water quality. Because anthias benefit from frequent feeding, effective filtration and consistent nutrient management are particularly important. Stability is more important than targeting one exact value within these ranges.
Common Considerations
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Female coloration: Females display a broad yellow dorsal region with softer lavender-to-pink coloration compared with dominant males.
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Frequent feeding: Benefits from two to three or more small meals of plankton-sized marine foods each day.
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Social hierarchy: Dominant individuals may chase subordinate anthias, particularly in confined aquariums.
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Sex transition: A female can transition into a male when the social structure of the group changes.
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Active swimming: Requires substantial open water along with multiple caves and sheltered areas within the rockwork.
