Yellow Coris Wrasse Care: Halichoeres chrysus

Yellow coris wrasses are members of the coris group, which are the rainbow wrasses. More often, you’ll see them listed as canary or yellow wrasses when you hunt for them in a fish store – and even then, things aren’t what they seem at first glance.

The yellow scales? Kind of a given. But yellow wrasses undergo two color phases. In the initial phase – when the fish is a juvenile – two black “eyespots” show on the dorsal fin. You also see a smaller dot at the caudal peduncle (the base of the tail). As the fish ages, it moves into the terminal phase (terrible name, isn’t it?). One of the eyespots fades away, leaving a single black spot on the dorsal fin. You may also get fine traces of blue in the caudal fin. And in certain males, you get fine lines of green along the face.

Here’s where the wrinkle comes in. The banana wrasse (Thalassoma lutescens) also sports a brilliant yellow color when it’s a juvenile. But they’re NOT the same fish. They grow twice as long (needing a bigger tank), aren’t even close to being reef-safe, and have an aggressive temperament yellow wrasses lack. And the difference is SUBTLE. Their yellow is a touch brighter, with green and orange stripes along the face. And those eyespots? ABSENT. You’ll want to make sure you have the right fish BEFORE you leave the fish store unless you want to cope with potential problems down the road.

Yellow coris wrasses frequent reefs from the eastern Indian Ocean through Micronesia and down to North South Wales. Divers have noted them between 60-200 feet, swimming in loose shoals. And the average wild wrasse lifespan is around ten years. But in a captive setting? You’ll probably see between 5-7 years – provided you stay on top of your care.

Aquarists love yellow wrasses because they feed on pests. They’re the nuisance clean-up crew of the saltwater aquarium world. And they aren’t picky. Given an opportunity, they’ll sweep tanks free of:

• Flatworms
• Fireworms
• Pyramid snails

It’d be nice if they tackled Aiptasia, but the starfish don’t appear on the menu. And while it might be tempting to add some wrasses to your current reef tank set-up, you need to keep some biology in mind. if you want them to thrive

The best choice is sand with a grain size of 5mm or less. This will allow your yellow wrasses to burrow without getting scratched. And you need a depth of at least 4 inches (10.2cm), so they have room to completely “submerge” themselves. Which they’re going to do for the first few nights (if not weeks) of entering the tank. It’s frightening for you, but as long as you have a properly-cycled saltwater system (and appropriate tank mates, which we’ll get to), it’s not a concern. They’re in a new environment, and that’s how wrasses react to strange situations – they hide their heads (and, well, bodies) in the sand.

With their hidey-hole (and bed) sorted, you want to turn to the remainder of the décor. Yellow wrasses enjoy exploring – once they feel comfortable. Live rock makes ideal places for them to swim through and around (not to mention a potential source for pests). It’ll also provide shaded areas. They enjoy plenty of strong lighting, but not FULL light. The rock offers a retreat from the “sun.”

Finally, you need a sturdy cover for your aquarium. A locked mesh lid is a MUST for yellow coris wrasses. These fish JUMP when their stress levels get too high. And if you opted for a bare-bottom tank when you couldn’t find the suitable sand, they have no hiding place. Without a mesh cover, you may come home to find bright yellow fish all over the floor. (And, no, they can’t breathe out of water) While this is a wrasse species that “plays dead” to fool predators, it’s not an act when they’re out of the tank.

Yellow Coris Wrasse Tank Size

Yellow coris wrasses don’t mind staying in small schools (think about 3-5 individuals) – and they look fantastic swimming through a marine tank together. They’re not the largest wrasse species, but you still need to provide plenty of room for everyone (not to mention enough sand space for the group). As such, your best bet is to aim for a 40-50 gallon (151-189L) aquarium.

Make sure you leave plenty of open swimming areas. You need that live rock for exploration, but yellow wrasses want to stretch their fins. If they get too crowded, they CAN start to become crabby. The aggression isn’t a regular part of their M.O., but if there’s limited swimming space (and as they get older), it’ll pop up. You’re better off scaling up on tank size (or scaling DOWN on school size).

Are Yellow Coris Wrasse Reef-Safe?

In theory, yellow coris wrasses have no problem sharing tank space with corals, anemones, or invertebrates. But you’ll want to exercise some caution before you add them to your reef tank. They burrow into the sand. And you chose fine-grained sand for your substrate. So as they dig, they’ll disperse sand into the water, which may harm some coral polyps. Yellow wrasses may also arrange smaller corals in their hunt for food. You’ll want to look at your coral species carefully before adding wrasses into the mix.

Also, yellow wrasses have no problem hunting down invertebrates. Feather dusters and tubeworms ARE natural parts of their menu. If you’ve gone through the trouble of cultivating these beauties, the yellow coris wrasse probably isn’t the fish for you.

Yellow Coris Wrasse Diet

Besides being a champion of saltwater aquarium pests, yellow coris wrasses select from the carnivore side of the menu. And as long as you keep up with their demanding feeding schedule, they’re not particularly difficult to keep fed and healthy. If you skip a meal, though, they may start harassing other members of the marine tank community.

Unlike other saltwater fish, you need to feed yellow wrasses THREE times a day – and that’s a minimum. Twice a day won’t cut it. They’re active fish with a high metabolism. And while you can use live rock or live sand to supply some pest material, it’s best not to rely on that as a definitive third meal. (You never know when it may run out – or if other tank mates are sharing in the bounty)

Yellow coris wrasse food is easy to come by:

• Blackworms
• Bloodworms
• Brine shrimp
• Marine flakes
• Mysis shrimp
• Nori

With one of the more docile personalities in the wrasse group, yellow coris wrasses do well in saltwater communities. They WILL dive into the sand if they get frightened (or attempt to “play dead”), but they don’t adopt aggressive displays or attitudes. And since they enjoy picking at pests, they often join the clean-up crew in the tank.

During the evening hours, yellow wrasses burrow into the sand for the night. This makes them active during the day, which keeps them popular with aquarists. They won’t interfere with nocturnal species, including the “night cleaning crew.”

Some of the best tank mates for yellow coris wrasses include:

• Boxfish
• Firefish
• Gobies
• Surgeonfish
• Other wrasses

Large, aggressive fish DON’T mix well with yellow coris wrasses. And if you have even a semi-aggressive fish that hates the color yellow? Yeah, big problem. (That’s right, fish have those kinds of issues) This means you’ll need to skip:

• Yellow angelfish
• Banana wrasses
• Damselfish
• Flame cardinalfish
• Lemon tangs
• Neon dottybacks

And while dragonets never hurt anyone, they DO eat the same copepods as yellow wrasses. Since the wrasses can swim faster (and eat more), you’ll end up with a starved dragonet. In the interest of fairness, skip pairing the two together.

Breeding the Yellow Coris Wrasse

Yellow coris wrasses are a sequential hermaphroditic saltwater fish species. Nearly all fish are born female (we’ll touch on the exception in a second). The fish then gather in large groups in the wild, where one will develop into a male, collecting a harem. However, there ARE super males in the yellow wrasse. There are fish that have a genetic code that sees them BORN male. It doesn’t happen often, but it WILL show up.

Figuring out if you have males or females is tricky. Females are a little smaller, and they don’t have quite the brilliant color of the males. Sometimes they have the initial phase double spots, too. But if you don’t know your fish’s age, that’s not something to bet on.

Breeding yellow coris wrasses in captivity isn’t the most straightforward task in the world. And that’s because you need a large harem to trigger the sexual change in the first place. This means purchasing a group of the same age fish all at once and introducing them into the tank. Because wrasses? They only spawn when completely comfortable. There are no known triggers. It’s spontaneous. In the wild, most harems feature one male and around 6-7 females. And if you want the best chance of success, you’ll need to follow suit.

There’s no parental care of the eggs or fry. So IF you get a successful spawning, you’ll want to transfer the eggs to a separate tank to allow them to hatch. You can then raise the fry until they’re large enough to rejoin the community.

Yellow coris wrasses look stunning. And they’re beneficial to saltwater aquarists. But they come with a few concerns you’ll need to manage. As with any fish species, it’s essential to look at both sides of the coin:

Pros

• Yellow coris wrasses don’t have a history of any particular diseases. They CAN scrape themselves during their digging, but you don’t need to worry as long as you don’t see irritation or loss of appetite.
• They feed on the most common pests in saltwater aquariums, allowing you to sigh with relief if you’ve struggled to keep flatworms or pyramid snails under control.
• The digging behavior in the sand is entertaining to watch – especially as your yellow wrasses bed down for the night.

Cons

• Yellow coris wrasses jump when frightened or stressed, necessitating a tight cover on the tank to prevent accidents.
• Through their digging behavior, yellow wrasses often disperse sand particles into the water, presenting problems for some corals.
• With a carnivorous diet, these wrasses HAVE been known to nip at and harass ornamental and cleaner shrimp – especially if not fed frequently enough.

Yellow coris wrasses add a vibrant yellow shade to the best marine tanks. And with their determination to eradicate the most annoying pests, they’re an aquarist’s best friend. So why wouldn’t you want to know more about them?

How cute is this? This YouTube video shows a yellow coris wrasse digging into the sand for the night.

Want to learn more about the best yellow wrasse tank mates?

What about those common saltwater pests?

Conclusions

Yellow coris wrasses have a shy, peaceful temperament. Combine that with their unique appearance and habit of cleaning up the tank, and you have the perfect saltwater species. And as long as you can handle their specific needs, they shouldn’t cause you any problems.

Just take a close look at the fish in the fish store. You don’t want to end up with a banana wrasse instead!

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