Despite its many many common names, no matter what you call it… the Yellow-brown Wrasse or Yellow Moon Wrasse is a bold, attractive, and hardy aquarium fish!

Thalassoma wrasses in general are very active hardy fish, and a joy to watch as their colors change with age. Just like all these wrasses, this fish stays just as beautiful as each phase begins and ends. But with its attractive color phases, the pretty Yellow-brown Wrasse has earned just about the most number of common names we have seen for one fish!

Its common name is the Yellow-Brown Wrasse or Yellow Moon Wrasse, but it is also known by such names as the Green Moon Wrasse, Sunset Wrasse, Banana Wrasse, Surge Wrasse, Lutenscen’s Wrasse, Yellow Wrasse, Whistling Daughter, Parrotfish, Blue Fin wrasse, and finally the Australian Lime Green Wrasse. Consequently, this fish is often confused (even by suppliers) with the Moon WrasseT. lunare, but can quickly be differentiated when compared to each other. It is also occasionally confused with the Sunset Wrasse T. grammaticum, because of some mix-ups based on where it is collected.

This active wrasse is hardy, easy to maintain, and long-lived in the aquarium. Gaining length up to almost 12″, it is necessary for the Yellow-brown Wrasse or Yellow Moon Wrasse to have plenty of swimming room. It is an excellent fish for the community aquarium as long as its tank mates aren’t too passive. This wrasse doesn’t bother corals but it will eat crustaceans, invertebrates, and small fish. When frightened this fish will hide in the rock work, rather than the sand like many of the Halichoeres wrasses and Leopard Wrasses. This makes them suitable for an aquarium with a shallower sand bed.

For more Information on keeping marine fish see:
Guide to a Happy, Healthy Marine Aquarium

Yellow-Brown Wrasse, Thalassoma lutescens

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A lively Yellow-Brown Wrasse male, sometimes mistakenly called the the “sunset wrasse”

The Yellow-Brown Wrasses, Thalassoma lutescens, is lively in action and in color! It has acquired many names due to the different color forms that appear between the juvenile phase and adult phase. Some mistakenly call them a Sunset Wrasse, but the true Sunset Wrasse Thalassoma grammaticum does not have a blue collar. They are easy to maintain but will reach almost 12″ in length, so will need a large tank to swim in during the day with rock work to hide among at night.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Labridae
  • Genus: Thalassoma
  • Species: lutescens
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Habitat: Natural geographic location:

The Yellow-brown Wrasse or Yellow Moon Wrasse was described by Lay & Bennett in 1839. Found in the Indo-Pacific from Southern Japan up to Ducie Island and Sri Lanka, you will also find this wrasse in the Hawaiian Islands, in south/southeastern Australia, and various islands in that area. They prefer outer lagoon and seaward reefs that are over open sand. They like dense coral growth but are usually found in shallow exposed areas at depths of 3 to 98 feet (1 – 30 meters). Interestingly, once you hit the tropical eastern Pacific the Yellow-brown Wrasse is replaced by the Sunset Wrasse Thalassoma Grammaticum which is found in Mexico, Panama, and the Galapagos Islands.

Status:

These fish are not listed on the IUCN Red List.

Description:

The Yellow-brown Wrasse or Yellow Moon Wrasse has acquired a wide variety of descriptive common names because of its various color stages as it ages. The juvenile is basically yellow and the female is the same only with a little green band behind the head. A young male is mostly green, has a yellow tail trimmed in pink. and a greenish yellow head that has reddish pink stripes. As the male ages a more brilliant contrast occurs in the head area, a blue band develops just behind the pectoral fins, the pectoral fins themselves are yellow and blue edged in black, and the tail fin becomes edged in pink. Secondary or terminal phase males (females that have changed into males) are the most brilliantly colored. There are also variations depending on the location the fish lives. Life span is unknown, though the Thalassoma wrasses are known to be long lived in the aquarium.

There is occasional confusion between Yellow-brown Wrasse or Yellow Moon Wrasse and some of the other Thalassoma species:

  • This wrasse is often confused with The Sunset Wrasse T. grammaticum. The name ‘Sunset’ is often mistakenly given to this wrasse. This is due to confusion as to its collection location. The actual Sunset Wrasse T. grammaticum is basically bright green and has a pink head with green stripes from the mouth to the gills. It is a solitary fish that travels a very broad range, so it is not often collected and rarely seen in the aquarium trade.
  • This wrasse is also often confused with the common Moon Wrasse or Lunar Wrasse T. Lunare, though the Moon Wrasse is easily differentiated, especially by the black dot in front of the back fin on juveniles.

Length/Diameter of fish:

Adults can reach up to about 11.8 inches (30 cm), though in captivity most Thalassoma wrasses only grow to about 6 or 7 inches (15 – 18 cm).

Maintenance difficulty:

These fish are very easy to keep and eat whatever food you may have for them. They adjust very quickly to aquarium life and prepared foods. Hardy beginner fish for a large aquarium. Generally not considered totally reef safe, though they will not bother your corals. They will eat small fish, ornamental shrimp, snails, serpent stars, bristleworms and mantis shrimps as long as the mantis is not too big. Good for a community aquarium with similar sized aggressive or larger tank mates.

Foods:

The Yellow-brown Wrasses or Yellow Moon Wrasses are carnivorous, in the wild they eat benthic hardshelled invertebrates such as crabs, snails, mussels, molluscs, worms, brittlestars, and sea urchins. Having very hearty appetites, they are easily trained to eat prepared foods in the aquarium. Feed a varied protein diet strong in small crustacea, formulas and frozen foods such as mysis and brineshrimp, and thawed chopped raw fish, and even flake foods. They are heavy eaters that will eat anything and need to be fed 2 or 3 times a day.

Maintenance:

Normal water changes at 10% biweekly or 20% monthly.
For more information see, Marine Aquarium Basics: Maintenance

Aquarium Parameters:


This fish needs to have plenty of room to swim and lots of rockwork to hide in if they get frightened.
Minimum Tank Length/Size:
A minimum 75 gallon (284 liters) or larger with a longer tank instead of a tall. A male and female may be housed together as long as the tank is 125 gallons or more.
Light: Recommended light levels
No special requirements.
Temperature:
No special requirements. Normal temperatures for marine fish is between 74° and 79° F (23 – 26° C).
Water Movement: Weak, Moderate, Strong
Some strong currents and some normal areas, like the ocean provides.
Water Region: Top, Middle, Bottom
They will spend time in all parts of the aquarium.

Social Behaviors:

They may only be together if a mated pair and in a large take over 125 gallons. Needs to be kept with other pugnacious fish and as they are highly predatious, will take out any small fish . If adding new fish, and they are smaller or similar in shape, they will harass them. Will not get along with other species of the same genus

Sex: Sexual differences:

Females are generally more yellow and have a green “band” behind the head. Males are more green and blue in the body area.

Breeding/Reproduction:

Not yet bred in captivity. Not much is known about their mating behaviors, but like all wrasses they will change sex when needed. They are open water spawners and do not protect their young.

Availability:

The Yellow-brown Wrasse or Yellow Moon Wrasse is often available. They can be found on the internet or as a special ordered through a pet store, ranging in price between about $100.00 to $120.00 USD.
Due to the species confusion (discussed above under description), do not be surprised if the supplier sends a Lunar Wrasse instead. Asking the pet store to have their supplier email a photo of this fish first is your best bet.