Yellow coris wrasse
Halichoeres chrysus
The Yellow Coris Wrasse is a bright yellow, active hunter of reef parasites. A peaceful beginner-friendly fish, it mandates a deep fine sand bed for nocturnal burial and a tightly covered aquarium.
Water Temperature
24 - 27 °C
pH Value
8.1 - 8.4
Water type
Marine
Tank level
Bottom and middle
Adult size
12 cm
Minimum tank volume
>= 250 L
Minimum group
>= 1
Species description
Geographical Origin and Habitat: Western and Eastern Pacific Ocean, including the coasts of Japan and Australia. Incessantly patrols coral reefs, sandy areas mixed with rubble and algae beds in search of small benthic invertebrates.
Taxonomy and Morphology: Yellow Coris Wrasse (Yellow Wrasse). Falsely known as "Coris", it belongs to the genus Halichoeres. Very hydrodynamic, slender and compressed, cigar-shaped body, specially evolved to cleave through the sand. Length 12 cm (4.7 inches).
Social Behavior: Very lively, peaceful and diurnal. Swims darting up and down the reef all day long. As soon as the lights go out (or if frightened), it dives headlong "like a dart" into the sand, burying itself completely to sleep safely.
Coloration and Sexual Dimorphism: Juveniles and females are a blazing solar yellow, with two evident false eyes (black ocelli) on the dorsal fin. As they grow and transform into terminal males, they lose the ocelli and develop thin dark green and pink vermiculations on the snout.
Care, breeding and tankmates
Aquarium Setup: Minimum 200-liter (55 gallons) reef. SAND REQUIREMENT: the bottom MUST be fine sand, at least 5-7 cm (2-3 inches) deep to allow nocturnal burial. Without sand it will stress to death breaking its snout on the glass or throw itself out of the tank. Lid absolutely necessary.
Diet and Feeding: Carnivore, tireless hunter of parasites. Easily accepts dry food (marine pellets, flakes), but must receive abundant frozen mysis and brine shrimp. Spends the day inspecting the rocks in search of plankton, eggs and parasites.
Water Quality: Extremely tolerant and robust (excellent for reef beginners). Temperature 24-27°C (75-81°F), specific gravity 1.023-1.025, pH 8.1-8.4. Actively contributes to the health of the aquarium by feeding on unwanted organisms that escape maintenance.
Compatibility and Cohabitation: The "Medic Fish" of the Reef: it is formidable for eradicating plagues such as red planaria (flatworms), montipora-eating nudibranchs and pyramidellid snails of tridacnas. Safe with all corals, but may bother small shrimp or delicate decorative tube worms.
Aquarium Breeding: Unknown in the home environment. Protogynous hermaphrodites (born female and change into males). In nature, mating takes place in the pelagic water column with the release of scattering eggs.
Risks and Diseases: Transport is very stressful (often travels buried in sand without eating). During the first week of introduction it may never come out of the sand for days. Stirring the sand to look for it means condemning it to death from a heart attack.
Geographic Origin and Distribution
Western and Eastern Pacific Ocean, including the coasts of Japan and Australia. Incessantly patrols coral reefs, sandy areas mixed with rubble and algae beds in search of small benthic invertebrates.
Origin
Tropical oceans and reefsEast AsiaAustralia, New Guinea, and Oceania
Fish profile
- Temperament
- Peaceful
- The Yellow Wrasse is celebrated for its bright color, peaceful disposition, and incredibly active nature, bringing constant movement to any reef tank. They are inquisitive and always 'on the go', meticulously inspecting the rockwork for their next meal. They are not shy once acclimated and will often greet the aquarist at the front glass, eagerly anticipating food. Their peaceful nature makes them ideal tank mates for a wide variety of fish, provided they are not housed with highly aggressive species. They are hardy, resilient, and provide excellent utility as natural pest controllers.
- Diet
- Omnivore
- In the wild, their diet consists almost entirely of small crustaceans, mollusks, and various pests found on the reef. In captivity, they must be provided with a varied, high-protein diet consisting of mysis shrimp, vitamin-enriched brine shrimp, and finely chopped seafood. Once acclimated, they are generally not picky and will eagerly accept high-quality marine flakes and sinking micro-pellets. Providing a diverse diet is crucial for maintaining their brilliant yellow coloration and robust immune system. Their natural hunting instincts make them an invaluable biological control for many common reef pests.
- Life expectancy
- 5-10 years
- The yellow coris wrasse has a very favorable life expectancy in captivity, being able to live between five and ten years in mature and well-managed marine aquariums. Its longevity depends heavily on the presence of a deep and fine sand substrate where it can take refuge every night, preventing chronic stress. A varied and abundant diet, combined with keeping nitrates at low levels, minimizes the occurrence of common diseases. The presence of non-aggressive tankmates also contributes to a long and healthy life.
- Adult size
- 12 cm
- The catalog's scalar value is 12 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 12 cm for this species, recorded as total length (TL). The taxonomic record consulted is Halichoeres chrysus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Group
- They are protogynous hermaphrodites, meaning all individuals begin life as females and the most dominant fish can eventually transition into a male. Males are distinguishable by the development of intricate green and pink facial markings that females lack. In a home aquarium, it is highly recommended to keep only a single specimen, as keeping multiple males will result in severe territorial fighting. A male and female pair can sometimes be kept in a very large tank, but aggression can still occur. A single Yellow Wrasse will live a long, healthy life as a stunning centerpiece.
- Feeding frequency
- Twice daily
- Due to their high energy levels and rapid metabolism, the Yellow Wrasse should be fed two to three times a day. Offering smaller, more frequent meals mimics their natural continuous foraging behavior and ensures they maintain a healthy weight. They are fast, bold eaters that will eagerly dart into the water column to snatch food before it sinks to the bottom. Care should be taken to ensure that slower or more timid tank mates receive adequate food during feeding time. Overfeeding should be avoided to prevent degrading the water quality in the aquarium.
- Bioload
- Medium
- The Yellow Wrasse produces a moderate bioload that is proportional to its highly active swimming behavior and frequent feeding requirements. As a carnivore with a fast metabolism, it processes food quickly, resulting in steady waste production throughout the day. An efficient protein skimmer and a robust biological filter are essential to keep the water pristine and prevent nitrate accumulation. Because they are messy eaters, uneaten food can easily become trapped in the rockwork, necessitating regular tank maintenance and siphoning. Overall, their bioload is manageable in most standard reef setups provided routine husbandry is maintained.
- Flow
- Strong
- They prefer an aquarium with moderate to strong water flow, which replicates the dynamic currents of their natural reef environment. Strong circulation is essential to provide the high oxygen levels these active swimmers require to thrive. The flow also helps keep detritus suspended, allowing the filtration system to process it effectively and keep the water clear. While they enjoy swimming against the current, they also need access to calmer areas within the rockwork where they can rest. Adequate surface agitation is crucial for promoting the necessary gas exchange for optimal health.
- Jump risk
- No
- Reproduction
- Oviparous
- Breeding the Yellow Wrasse in a typical home aquarium is exceptionally rare and virtually impossible for the average hobbyist. They are pelagic spawners that require a massive vertical water column to perform their courtship dances and release their gametes. The fertilized eggs become buoyant and drift in the ocean currents as part of the plankton before hatching into microscopic larvae. The specific dietary needs of these larvae and the required environmental cues are beyond current captive capabilities. Consequently, all Yellow Wrasses available in the trade are ethically sourced from wild populations.
- Compatibility & tankmates
- Territorial
- They are considered one of the most peaceful and highly desirable 'reef safe' wrasses available in the hobby. They get along excellently with a wide variety of community fish, including tangs, clowns, dwarf angels, and blennies. While they generally ignore corals, they are natural predators of small benthic invertebrates and will enthusiastically hunt down flatworms, pyramidellid snails, and small bristle worms. They can pose a threat to very small ornamental shrimp or feather dusters, though large cleaner shrimp are usually safe. They should not be kept with overly aggressive predators or large, territorial wrasses that might bully them.
- Tank level
- Middle/Bottom
- They are highly active fish that utilize the entire aquarium, constantly darting in and out of the rockwork to hunt for pests. A soft, fine sand bed of at least two to three inches deep is a non-negotiable requirement for this species. They sleep completely buried in the sand every night and will instantly dive into it if they feel frightened or threatened. Tanks with bare bottoms or coarse crushed coral are completely inappropriate and will cause severe stress and physical injury. They need a balance of complex rockwork for hunting and open space for swimming.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3.4 ± 0.5 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.5
- Bayesian Length-Weight
- a = 0.01, b = 3.09
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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