A yellow wrasse is a type of marine fish native to tropical waters. Commonly found around the coasts of Australia, the Solomon Islands, and in the Indian Ocean, these fish are also popular in saltwater aquariums. The scientific name for the yellow wrasse is Halichoeres chrysus.
Also called canary wrasses, yellow wrasses are a solid bright yellow. They have one long dorsal fin, or fin on their backs, which stretches from just behind their heads nearly to their tails. On juveniles, there are three evenly spaced black spots ringed in white on this fin. The males retain one spot throughout adulthood. Though they are considered a medium-sized wrasse, these fish are usually only about 5 inches (12.7 cm) long.
In the wild, these wrasses are found around coastal reefs, near sandy bottoms with lots of rocks and other rubble. They may be found at depths of 6.5–197 feet (2–60 m), but are most often found at 49 feet (15 m) or below. Bottom feeders, they generally eat snails, shrimp, and other small invertebrates common to reef habitats. They are sometimes, but not always, found in schools.
Not aggressive fish, yellow wrasses are often considered a good choice for saltwater aquariums because they will eat many pest species, such as flatworms and pyramidellid snails. This makes them good protection not only for coral, but clams as well. Additionally, they will often clean parasites from other fish. Although they are found around reefs in the wild, these fish are not always completely safe to have in reef tanks because in addition to eating pest species, they also eat some beneficial species.
Setting up an aquarium for a yellow wrasse requires 2–3 inches (5–7.6 cm) of sand on the bottom of the tank. When the wrasse feels threatened, it will burrow into the sand and hide. This will be its initial behavior for the first few days when introduced to a new tank. In addition to sand, rocks and other shelter areas should be added to the tank. Any aquarium that houses a yellow wrasse should be covered since these fish are good jumpers and will jump out of the tank given the opportunity.
To keep the wrasses healthy, water temperature should be kept between 72–78°F (22.2–25.5°C), and the water's pH should be between 8.1–8.4. A 30–50 gallon (113.5–189 L) tank is the recommended minimum size for these fish. Many experts do not recommend the yellow wrasse for beginning fish owners.