Six Line Wrasse (Pseudocheilinus Hexataenia) saltwater aquarium fish

Overview:

The Six Line Wrasse (Pseudocheilinus hexataenia) is a hardy, active marine fish that does best in a mature, stable reef aquarium. It is highly adapted for swimming through rockwork and spends much of its time picking at surfaces, so the ideal setup includes a tight-fitting lid, plenty of live rock, and multiple hiding places. A tank of at least 55 gallons is recommended, with strong filtration, good oxygenation, and stable water quality. This species prefers tropical marine conditions: temperature around 74–78°F, salinity 1.023–1.026, and clean, well-circulated water with minimal sudden changes. Because it is territorial and quick-moving, it benefits from a carefully planned environment with enough visual barriers to reduce aggression.

Diet and Feeding:

Six Line Wrasses are carnivorous micro-predators that feed on small meaty foods in the wild, including worms, tiny crustaceans, and other invertebrates. In captivity, offer a varied diet of high-quality frozen foods such as mysis shrimp, brine shrimp, finely chopped seafood, and enriched marine pellets or flakes designed for carnivorous fish. Feed small portions 1–2 times daily, only as much as the fish can consume quickly. A varied diet helps maintain strong coloration, energy, and immune function. Because this species is active and opportunistic, it may also help control some nuisance pests like flatworms and small bristle worms, but it should not be relied on as a sole pest solution.

Compatibility:

Compatibility can be challenging despite the species’ small size. Six Line Wrasses are often assertive, especially as they mature, and may become aggressive toward other peaceful wrasses, slow-moving fish, and similar-shaped species. They may also harass smaller tankmates or newly introduced fish. Best tankmates are robust, similarly sized fish that can tolerate a confident, active wrasse, such as many tangs, clownfish, gobies, and dartfish in appropriately sized tanks. Avoid keeping them with other Six Line Wrasses or very similar wrasse species unless the aquarium is large and carefully managed. In reef tanks, they are generally considered safe with corals, but they may prey on small ornamental crustaceans such as tiny shrimp, amphipods, or very small crabs.

Health and Quarantine:

Six Line Wrasses are usually hardy once established, but they are still vulnerable to common marine diseases such as marine ich, velvet, and bacterial infections from stress or poor water quality. Quarantine is strongly recommended for 2–4 weeks before introduction to the display tank. During quarantine, observe feeding behavior closely, treat parasites if needed, and ensure the fish is eating aggressively. Provide a covered quarantine tank with hiding places and stable conditions to reduce stress. Preventive care should focus on excellent water quality, a consistent feeding routine, and minimizing aggression from tankmates. Because wrasses are jumpers, secure aquarium lids are essential in both quarantine and long-term housing.

mysis shrimp brine shrimp high-quality marine flakes/pellets
The Six Line Wrasse is an active, constantly patrolling swimmer that uses the full water column and benefits from a tank with ample live rock, crevices, and hiding spots. It is generally bold and semi-aggressive, often becoming territorial, especially toward conspecifics, which are usually best avoided unless kept as a bonded pair in a very large system. A minimum tank size of 30 gallons is commonly recommended, though more space is preferred, and a rockwork-rich layout with visual barriers helps break up sightlines and reduce chasing behavior. In reef aquariums, it is typically reef-safe and coexists well with sturdy, similarly sized tank mates, but can harass shy or passive species and may intimidate smaller wrasses or slow feeders. Its diet is carnivorous to opportunistically omnivorous, with a strong preference for small invertebrates, worms, copepods, and other tiny prey it hunts among the rockwork. Regular meaty prepared foods are usually accepted, but access to natural microfauna helps support its active foraging behavior and overall condition.

FAQ

Frequently Asked Questions

About the Six Line Wrasse

  • Why does my Six Line Wrasse keep harassing new tankmates, especially small gobies and other peaceful wrasses?
    Six Line Wrasses are naturally territorial and can become highly aggressive as they mature, especially in smaller aquariums. They often view similarly shaped or similarly colored fish as rivals, and they may relentlessly bully timid species. To reduce aggression, add the Six Line last, keep it in a larger tank with plenty of rockwork and sight breaks, and avoid mixing it with other wrasses of similar body shape unless the system is large and carefully planned. Once a Six Line becomes established, rehoming may be the only reliable fix if it turns into a tank bully.
  • What is the minimum tank size for a Six Line Wrasse, and why do they need so much swimming space if they’re a small fish?
    Although Six Line Wrasses stay small, they are extremely active, constantly patrolling rockwork and hunting for microfauna. A single specimen is best kept in a tank of at least 55 gallons, with 75 gallons or more being much safer if you want to reduce aggression and provide enough territory. They need more than just open water; they require a mature aquascape with lots of caves, crevices, and live rock to explore, sleep in, and forage through. Small tanks tend to amplify territorial behavior and stress.
  • Will a Six Line Wrasse eat flatworms and bristleworms, or is that just a myth?
    They often do, but results vary by individual. Six Line Wrasses are known for picking at small pests such as flatworms, pyramidellid snails, copepods, and bristleworms, and many hobbyists keep them partly for this reason. However, they are not guaranteed pest-control fish, and they may ignore some pests entirely if enough natural food is available. They should not be relied on as a sole solution for an infestation, and once pests are gone, their diet still needs to be supported with meaty frozen foods and plenty of natural grazing opportunities.
  • Why is my Six Line Wrasse refusing prepared foods even though it is active and looks healthy?
    Newly acquired Six Line Wrasses often feed heavily on pods and small invertebrates in the rockwork before accepting frozen or pellet foods. If it is active and hunting, it may simply be relying on natural forage. Try offering small meaty foods like mysis shrimp, finely chopped seafood, enriched brine shrimp, and high-quality small pellets multiple times a day. A mature tank with abundant copepods helps bridge the transition. If a newly imported fish ignores food for several days but remains alert and swimming normally, that can be typical; if it becomes thin or lethargic, intervene quickly.
  • Can a Six Line Wrasse jump, and what kind of lid do they actually need?
    Yes, they are excellent jumpers and one of the wrasse species most likely to end up on the floor if the aquarium is not tightly covered. A fully sealed lid or very well-fitted mesh top is strongly recommended, with no gaps around plumbing, wires, or corners. Even a healthy, established Six Line can jump when startled, chased, or during lights-out. If you keep one, assume it will eventually test any opening and secure the tank accordingly.