Mystery Wrasse (Pseudocheilinus ocellatus): Ultimate Care Guide


Mystery Wrasse, also known as Whitebarred Wrasse, is an uncommon and striking species for marine aquarium hobbyists. Found in coastal waters and coral reefs in the West to Central Pacific, this carnivorous fish lives close to its preferred food source: invertebrates.

Mystery Wrasse Care

In general, Mystery Wrasse aren’t difficult to care for and they are relatively easy to feed. They aren’t picky eaters. Unfortunately it also has a tendency to eat smaller tank invertebrates. Common cleanup crew members are at risk with this species, especially as the fish grows and matures. They will also eat copepods and cultured brine shrimp. It is probably a good idea to maintain a refugium for copepod cultivation. Brine shrimp are another easy to produce live food that your Mystery Wrasse will appreciate.

This is a diurnal species which stays active in the day and sleeps at night. Unlike other Wrasse, the Mystery Wrasse doesn’t bury itself in sand. They sleep in cocoons, or mucous nets which can suffocate them at night if there isn’t enough water flow.

Let’s look at some things you’ll need to know when caring for this colorful and unusual fish!

Temperature

Mystery Wrasse do best with water temperatures between 72° and 78° F.

Water pH

Mystery Wrasse prefer pH in a range of 8.0 to 8.4.

Mystery Wrasse Size

Mystery Wrasse can reach a maximum size of 4 3/4 inches. As they mature, they can begin to cause troubles in a tank. A full-sized Mystery can have issues with other tank mates, particularly invertebrates. Your cleanup crew will be in possible jeopardy as this species increases in size.

Mystery Wrasse (Pseudocheilinus ocellatus)
Mystery Wrasse (Pseudocheilinus ocellatus)

Food & Diet

Mystery Wrasse are carnivores and should be fed a diet of meaty prepared foods such as vitamin enriched frozen mysis shrimp and vitamin enriched frozen brine shrimp. It can be a good idea to culture mysis shrimp and or brine shrimp to give this species ample access to live foods. It is important to use very high quality live or vitamin enriched foods as this species will willingly eat foods that don’t provide enough nutrition. Their health can suffer even though they appear to be eating well.

Mystery Wrasse will eat copepods and pick over live rock. If you have a refugium to cultivate copepods this can add some variation to your Mystery’s diet.

Mystery Wrasse Lifespan

Mystery Wrasse can live an average of 5 years with quality care.

Mystery Wrasse Tank Size

Mystery Wrasse need large tanks. 70 gallon or larger is best. Not only are they active swimmers but they can be somewhat aggressive. A larger tank will allow tank mates places to hide when necessary.

Tank Setup

Mystery Wrasse are somewhat different than other Wrasse and do best with a slightly different tank setup. Sand is less of a concern but current flow and rock availability need extra attention. Lets take a look at the best way to arrange a habitat for this species.

How to setup a habitat for Mystery Wrasse

The best setup for Mystery Wrasse will focus on four elements: large enough tank volume, sufficient anchor points for their cocoons, correct water currents and safety for any invertebrates.

Unlike other Wrasse, Mystery Wrasse do not bury themselves in sand. They do not need a deep sand bed. It’s fine if you have deep sand, this species will not disturb it.

Ensure you have a tank volume of around 70 gallons or more, particularly if you plan on keeping your Mystery with other tank mates. This species can become somewhat aggressive and a larger tank can reduce stress on all aquarium inhabitants. Some Internet sources state a 30 gallon minimum tank size. This would likely be enough when your Mystery is young. As this fish grows and matures it will become more aggressive and territorial. This species is a carnivorous predator and can sometimes go after other fish. A larger tank can be a big asset as the years go by.

When sleeping, Mystery Wrasse will build cocoons, or mucous nets. These will need something to attach to, usually rock caves or other suitable hardscape. You’ll want rock aquascaping with many nooks and crannies this species can build in.

One downside of sleeping in cocoons is the necessity of water flow. If there isn’t enough current your Mystery can suffocate inside their cocoons while sleeping. Make sure you have enough properly positioned wave makers. Be on the lookout for dead spaces. You’ll need to have some current coverage in all areas of your tank. This may require the use of more than one wave maker, especially if working with a 70 gallon or larger tank.

Choosing a cleanup crew can be a challenge with a Mystery in the tank. In the wild this species eats invertebrates and will be a threat to shrimp as they grow larger. Even a Goby won’t be completely safe from a 4 ¾ inch Mystery Wrasse. When young this species will likely be tolerant of your cleanup crew. As they grow above the 3 inch mark it might be time to move them to another tank or otherwise separate them from your diverse community tank.

Do Mystery Wrasse need sand?

Mystery Wrasse don’t bury themselves in sand like other Wrasse, so sand is not a requirement. This makes their stay in a mostly bare quarantine tank (QT) easier. Even in a QT they will want to build sleeping nets and should be provided with wave makers, rock caves and other appropriate hardscape features.

Are Mystery Wrasse Reef Safe?

Mystery Wrasse will not harm corals but can attack other common inhabitants of a reef tank. A young Mystery will likely behave well in a reef environment, but can pose a danger as it grows. Members of your cleanup crew will be the first victims: shrimp will eventually be on the menu for a growing Mystery. Even Gobies won’t be safe when this species is fully grown. If adding to a reef environment keep a watchful eye and prepare to move your Mystery Wrasse to another tank as it grows.

Mystery Wrasse Tank Mates

Mystery Wrasse are often kept alone to avoid possible problems with other fish and invertebrates. Exercise caution when mixing this species into a community tank.

Are Mystery Wrasse Aggressive?

Young Mystery Wrasse are not excessively aggressive but this can change as the fish matures. Larger specimens can be territorial and will be a threat to invertebrates and some smaller fish. This species is a carnivorous predator in nature and may eventually tire of eating prepared food. Keep an eye out for aggression and have a plan to move it to another tank environment if necessary.

Examples of Compatible and Incompatible Tank Mates

Mystery Wrasse will have similar pairings to Lined Wrasse. They will do best with semi-aggressive or larger species. Avoid smaller fish, shrimp, crabs or other invertebrates. Mystery will probably not harm tangs or surgeonfish. Likewise, angelfish and puffers can be good matches. Having a regular cleanup crew can be an issue as many shrimp or crabs are easy targets for a larger Mystery.

Every fish has its own personality and your Mystery Wrasse may be well behaved, particularly if provided a larger tank. As this species grows the chance for violence against tank mates increases.

Mystery Wrasse Breeding

Currently, Mystery Wrasse have not been bred in captivity. All specimens in the aquarium trade are wild caught. Wrasse are notoriously hard to breed in captivity. Even if they successfully spawn it is difficult to raise the fry past the larval stage.

Mystery Wrasse Male or Female

Mystery Wrasse are protogynous hermaphrodites and are all born female. They will transition to male depending on environmental triggers. Most hobbyists will only keep a single Mystery but if you decide to experiment with more than one, the larger specimen will often become male. That is if they even tolerate the other’s presence.

Mystery Wrasse Disease

Mystery Wrasse are a known as a being resistant to Ich. They can be stricken with various maladies like Brooklynella and Velvet. Even though they are resistant to infection they can be carriers that can infect other fish. When adding a new Mystery to an existing tank make sure to quarantine it for a few weeks and observe closely. Use caution with Mystery Wrasse as they can be carriers for disease that won’t show on themselves but will infect others.

Where can I find Mystery Wrasse for sale?

Mystery Wrasse are a somewhat rare and expensive fish to obtain. Be prepared to placed on a waiting list unless you get lucky. Ask at your local fish store and check online. They can also be fairly expensive. Occasionally they can be had for 100 USD but more often they will range up to 200 USD. Prices have come down as they have become more popular.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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