Melanurus Wrasse Care & Info | A Rainbow For Your Tank

If you’re just starting out in the world of marine fishkeeping, the choice in fish can be pretty overwhelming. There are so many beautiful species out there, but many are difficult to keep if you’re not experienced in the hobby. Which to pick?

May we introduce the Melanurus wrasse? A great starter wrasse, this species is peaceful, mostly reef safe, and eats annoying pests. Does it get any better?! Keep reading below for everything you need to know about Melanurus wrasse care.

Melanurus wrasse description & natural habitat

Description

If you’re looking for a pop of color for your aquarium, you’ve definitely found it with the Melanurus wrasse. These flashy, elongated fish feature an almost psychedelic pattern of horizontal stripes in red, green, and bright blue. They reach a maximum length of around 5″.

Juvenile wrasses sport slightly duller colors and eye-spots on the fins to confuse predators. The same goes for the females, although those can change: Melanurus wrasses are hermaphrodites. In the wild, males manage harems of females. If they die or disappear, one of the girls will start turning male to replace them—sometimes within a day or two. This process can even be reversed if the male comes back!

In our tanks, where there are no other fish present, female wrasses will usually turn into males. Given the boys’ more vibrant colors, that comes in handy for us aquarists.

Natural habitat

The Melanurus wrasse is naturally found in the tropical western Pacific Ocean, from Thailand to as far east as the islands of Vanuatu. Here, it’s not fussy about the specific habitat type: it inhabits all sorts of reefs and rocky, shallow areas down to around 80ft deep.

The IUCN Red List considers Halichoeres melanurus to be a species of Least Concern in the wild. Although the reefs it inhabits face significant pressure from human activity, this species’ adaptability as a generalist in both habitat and diet has allowed it to thrive even in degraded reef environments.

One study suggests that the Melanurus wrasse is actually more abundant on degraded reefs than on healthy ones.

Melanurus wrasse aquarium

If you’d like to keep a Melanurus wrasse, go for an aquarium of 55 gallons or up to accommodate its adult size and give it plenty of space to dart around in search of food.

Lots of nooks and crevices make ideal hunting grounds, and you’ll see your wrasse patrolling and foraging throughout the day. The species is very entertaining to watch while they stalk and hunt copepods and any other small critters they can find.

A sandy substrate is appreciated, since like many wrasse species, this one likes to burrow. Try to use enough sand that the fish is able to completely bury itself: that’s when it feels safest and most comfortable, especially during the night.

Normal reef parameters work well for these wrasses: they’re known to be hardy and unfussy for a reef fish, though always keep the tank clean.

Did you know? Keep in mind that you’ll have to make sure your aquarium has a lid. Wrasses, like many other fish, are prone to jumping when they feel threatened by some real or perceived danger.

Melanurus wrasse compatibility

The nice thing about Melanurus wrasses is their peaceful attitude towards tankmates. Unlike some of their cousins in the family Labridae, like the six line wrasse (beautiful but a nuisance!), they generally won’t bother other fish.

One thing that does have to be noted is that Melanurus wrasses don’t appreciate the presence of their own and similar species in their territory. Unless you have a very sizeable tank, it’s best to stick to only one wrasse. If you do want multiple Melanurus wrasses, it may be a good idea to avoid keeping multiple males, instead opting for a pair or harem.

As for other tankmates, avoid very small and docile ones, as those may be stressed out by the wrasse’s super-high activity level. You can try clownfish, cardinalfish, or one of the many goby species out there.

Please note: the Melanurus wrasse is generally listed as reef safe ‘with caution’. It usually doesn’t bother corals. Small inverts won’t be safe, though, so make sure you don’t combine these wrasses with your prized (cleaner) shrimp, snails, or the smaller crab species.

Melanurus wrasse diet

The reason most aquarists end up acquiring a Melanurus wrasse is because of the species’ diet. It isn’t just an easy eater, but it hunts small invertebrates, many of which are nuisances in the aquarium. They’ll make quick work of pyramidellid snails, flatworms, Montipora-eating nudibranchs, and various other pesky critters and hitchhikers you’d rather not see in your tank.

Although buying a fish to deal with an infestation isn’t always the best idea due to compatibility issues or hyper-specific diets, this is usually not the case with this gentle and versatile wrasse. Once it eradicates any pests that might be present, it’ll usually switch readily to commercial fish foods rather than starving or turning to eating its tankmates.

Feed a meaty diet with plenty of frozen or live foods like mysis, along with regular pellet or flake options. You can also offer the occasional clam or shrimp, which will usually be devoured with gusto, and maybe some nori seaweed sheets from time to time.

Tip: Because these wrasses are so voracious, it’s best to feed them small amounts multiple times a day rather than concentrating everything in one big meal.

Breeding the Melanurus wrasse

Can it be done? Yes, it can and has been done; the first controlled Melanurus wrasse clutches were raised in 2015 by Rising Tide Conservation. In 2021, another study provided more details on the process. Despite this, the species still isn’t bred commercially, and the specimens in your local aquarium store are wild-caught.

Is breeding these wrasses something you can do at home? That depends on your level of dedication. A clutch of wrasse larvae is almost as needy and expensive as a human baby, but with a much lower success rate. If that somehow sounds good to you, here’s what we know.

As mentioned, these wrasses naturally occur in harems of one male and multiple females; obtaining a male is easy, as when one is lacking, a female will take up the role of the man of the house.

Unfortunately, these fish are pelagic spawners, meaning their eggs aren’t attached to anything but float freely in the water column. Pelagic spawners are pretty much always more difficult to breed.

It works a little like this:

• Around sundown, the male begins displaying for the females. Once one of them accepts, thousands of tiny floating eggs will be produced and fertilized.
• The eggs should be moved to a broodstock tank, such as with a (DIY) egg collector. This prevents predation by the parents.
• Hatching happens very quickly; it takes between 14-26 hours depending on the water temperature.
• The fry live off their yolk sacs at first and are ready to accept their first feeding of abundant newly hatched Parvocalanus crassirostris copepod larvae and green water after 3 days.
• Rising Tide suggests that metamorphosis will be delayed unless there’s a sandy substrate present. They added this around day 15 and the larvae burrowed in there to metamorphose at day 22.

Despite high densities of algae (green water) and copepod nauplii in the water, the 2021 study notes that larval loss is very high. If you fail, just try again—and be sure to share your experiences in the comments.

Conclusion

A beautiful saltwater aquarium with colorful fish like the zippy Melanurus wrasse is a joy to see. However, everyone has the time or knowledge to start and maintain one.

If you want your own reef but aren’t ready to invest hours into set-up and maintenance, you can contact us: FantaSEA Aquariums designs, builds and maintains custom tanks. What does your dream aquarium look like?