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Leopard Wrasses Demystified

With a label of “expert only” marked all over leopard wrasses, many aquarists have avoided these peaceful beauties.  Unfortunately, most LFS often bring them in knowing their dismal survival rates.  So where’s the compromise?  The secret is just a little bit of extra care up front for long-term health.

Xenojulis margaritaceus

Background

“Leopard Wrasse” is a common name for wrasses of the genus Macropharyngodon.  Below is a list of several leopard wrasses along with their common names (where available).  In this article, I’m also including the “Golden Nugget” wrasse, Xenojulis margaritaceus, since it looks, acts, and has similar health concerns as the typical leopard wrasses.

  • Macropharyngodon bipartitus (“diamond wrasse”, “divided wrasse”, “vermiculate wrasse”)
  • Macropharyngodon choati (“Choat’s wrasse”, “red-flecked wrasse”)
  • Macropharyngodon cyanoguttatus (“blue-spotted wrasse”)
  • Macropharyngodon geoffroy (“Geoffroy’s wrasse”, “short-nosed wrasse”)
  • Macropharyngodon kuiteri (“Kuiter’s wrasse”, “black leopard wrasse”)
  • Macropharyngodon meleagris(“black-spotted wrasse”, “guinea fowl wrasse”, “reticulated wrasse”)
  • Macropharyngodon moyeri
  • Macropharyngodon negrosensis (“black wrasse”, “negros wrasse”, “yellow-spotted wrasse”)
  • Macropharyngodon ornatus (“ornate wrasse”, “false leopard wrasse”)
  • Macropharyngodon vivienae (“Madagascar wrasse”)
  • Xenojulis margaritaceus (“finspot wrasse”, “pearly rainbowfish”, “golden nugget wrasse”)

As of October 2012, these fish are all considered of the “least concern” by the IUCN Red List of Threatened Species.  However, this status should not rationalize the aquarium importation rate of these delicate fish.

Most species of Macropharyngodon inhabit shallow sandbeds and the rubble near reefs.  This habitat supports their constant search for microfauna, which includes copepods, amphipods, and other small crustaceans.  These wrasses also dive into the sandbed for protection at night or when severely threatened and breathe through a tiny hole in the sand.

Wrasse breathing through a hole in the sand

Wrasse breathing through a hole in the sand

At night, wrasses expel a mucus substance from their mouths to create a protective net in which to sleep.  This mucus helps protect them against parasites, and it may help conceal them further from predators by masking their odor.  Additionally, this mucus layer may act as a sunscreen by absorbing UV (Zamzow, 2003).  Waking a wrasse may have deleterious effects as the wrasse uses 2.5% of its daily energy in creating the net.  Additionally, approximately 95% of wrasses that had their protective coating removed were attacked by parasites in comparison to only 10% with the coating (Gutter, 2010).

Preparing for the Wrasse

Bringing home a new inhabitant for the aquarium requires advance preparation and research (good thing you’re reading this, huh?)  Leopard wrasses are no exception and require a bit more preparation than other fish.

Approximately 75-85% of imported marine fish have intestinal worms (Bassleer, 1996), so I believe it is best to treat all new inhabitants as though they, too, are infected.  Since leopard wrasses nearly constantly search for food, having internal parasites lessens the nutritional value of their meals.  This can quickly lead to starvation, especially in a quarantine system where the pod population is not established.

Starving wrasse due to jaw deformity

Starving wrasse due to jaw deformity

Taking all these factors into account, my wrasse quarantine aquarium is a bit different than the typical quarantine. I use a 10g kit (found at most chain pet stores) that contains a lid, light, hang-on-the-back (HOB) filter, and a heater.  I also use an air pump sponge that has been in another aquarium for at least 24 hours.  This sponge will contain beneficial bacteria and possibly some pods.  I place a layer (about 3″ deep) of very fine sand in the aquarium and fill it the rest of the way with saltwater from my main aquarium.  I add the recommended dosage of Amquel (an ammonia detoxifier) in case of any dieoff during the setup.  Before bringing the wrasse home, the tank should be at the proper salinity (best to know what salinity your LFS keeps their tanks ahead of time) and temperature.  Also, try to find a source of live foods (baby brine shrimp are excellent for several reasons) beforehand.

Quarantine for Wrasses

Quarantine for Wrasses

Sponge air-powered filter

Sponge air-powered filter

Choosing the Wrasse

Species selection is up to personal preference and budget.  M. melagris is usually the most common in the aquarium trade, and it makes a great starter leopard wrasse due to its beauty and lower cost.

M. melagris

M. melagris

Work with your LFS to bring in the wrasse.  When the wrasse first arrives, it will usually dive straight into the sandbed for protection.  It also probably hasn’t slept in at least a week due to shipping, jet lag, lack of sandbed at the wholesaler, etc.  It also probably hasn’t ate in that long as well.  Since wrasses usually create a cocoon for protection from parasites, they aren’t usually very susceptible to cryptocaryon irritans (marine ich).  But, since they probably weren’t able to sleep in the sand during transportation, they weren’t able to make this protective net to prevent infection.  This combination is what earns the leopard wrasse the label of “expert only”.

M. bipartus in the bag

When the wrasse finally comes out (may be up to a week or more), it will be very hungry.  Ensure live foods are readily available for it.  Make sure it is eating before purchase!  A healthy wrasse will not turn down live food.  Better yet, see if the wrasse will accept frozen mysis or even pellets.

Check the body condition of the wrasse.  Look for jaw deformities as these commonly occur when a wrasse dives for protection and hits a solid surface (like the bag, tank bottom, rocks, etc.)  Look for signs of marine ich, cuts, or infection (red streaky areas).

Wrasse with broken jaw

Wrasse with broken jaw

The wrasse should be actively searching for food and not acting neurotic.  Although wrasses often act groggy when first emerging from the sandbed, they should swim with a purpose after a few minutes.  Avoid wrasses that swim in circles, sideways, or upside down as they may have swim bladder or neurological damage.

Bringing the Wrasse Home

Of course, bring the wrasse home as safely and quickly as possible just like any other fish.  Various theories on acclimation abound, but in my experience, getting these fish into the quarantine tank quickly after a temperature acclimation in the bag (assuming the salinity and pH are the same) is the best route.

If the wrasse does not immediately bury itself, I feed live baby brine shrimp along with a few pieces of mysis.  The live food will encourage the wrasse to eat, and the mysis is more substantial food.  Remove any uneaten nonliving food within a few minutes to prevent water fouling.

Treating for Internal Parasites

Since the wrasse probably has internal parasites and probably won’t get sufficient food in the quarantine, it’s extremely important to make what food it does get count.  I use PraziPro, a very safe (but effective) praziquantel medication, to treat for a wide variety of flatworms, tapeworms, and other internal parasites.  I follow the manufacturer’s directions for 7 days.  I do not run carbon during this time to keep the medication in suspension.  Usually by the end of this treatment, the fish are really starting to eat.

Treating for Marine Ich

As much as I can be sure, my main tank does not contain marine ich since I treat all fish/corals/etc before they are introduced.  Wrasses are generally not very susceptible to marine ich, but they can get it, especially during the shipping process.  (Barebottom holding tanks can exacerbate this problem as the wrasses do not have the extra protection of the sand.)  Therefore, I treat them regardless of whether they show signs of infection.

My treatment choice is hyposalinity.  Hyposalinity is very safe as the fish does not have to work as hard to maintain osmotic balance (regulating the fish’s internal salinity with the aquarium’s salinity.)  Since the fish does not have to work as hard, it can spend more of its energy healing and fighting infections.

After the PraziPro treatment (do not combine treatments), I start running carbon and perform a water change (replacing with RO/DI water buffered to the correct pH and at the same temperature) to reduce the salinity by 5 ppt.  I only reduce the salinity by 5 ppt per day in order to not stress the fish until the salinity reaches 14-16 ppt.  The internal salinity of marine fish is 11-12 ppt, so hyposalinity is safe for the duration of quarantine.

Since the salinity-lowering water changes only occur for a few days and there is not enough bacteria to support a fish, regular water changes (at the correct hyposalinity) are important.  I also use Amquel daily to detoxify any ammonia.

During hyposalinity, I continue feeding live baby brine shrimp that I hatch myself (instructions).  Brine shrimp are able to tolerate a variety of salinities, and they are able to survive in hyposalinity for a few days.  They also keep the wrasse entertained with a hunt.  I also feed mysis with the brine shrimp since quarantine is a good time to transition fish to new foods.  Toward the end of the 6-week hyposalinity treatment period, I introduce pellet foods as well.  So far, all of my leopard wrasses have ate everything I’ve tried.

Searching for food

Searching for food

After six weeks, I slowly bring up the salinity – only raising it 2 ppt per day.  Once the salinity is up to the display tank salinity, I put a bit of the quarantine water into a 5 gallon bucket, add an airstone, add the fish, and then start drip-acclimating the fish to the display tank (the display tank water drips very slowly into the bucket.)  Once the temperature/salinity are the same, the fish is almost ready to go in.

Display Introduction

In order to introduce fish successfully, I believe you have to do one of the following:  scare them, distract them, change territory lines, and/or surprise them.  For health reasons, scaring isn’t the best option in my opinion.  Changing rockwork is a good way to upset territorial lines, but my rockwork is fixed.  So, I’m left with distracting and surprising.  Before introducing the new wrasse, I turn off the main lights and then feed all the fish.  This distracts them and reduces fighting over food.  Then I add the new fish once some of the fish start to go to sleep.  When the fish awaken the next day, they’re all introduced to the new fish at differing times…and they’re surprised at how a newcomer got in.  There was no obvious introduction where all the current fish could gang up on the new wrasse.  Also, this is best since wrasses tend to dive straight for the sandbed.  Just let it go to sleep as if it was any normal night.

Checking each other out (female on left, male on right)

Checking each other out (female on left, male on right)

I came across an interesting scenario when I introduced my Xenojulius to my mated pair of M. melagris.  The Xeno was a bit larger than both the others, so I wondered if it would pick on the smaller two.  Interestingly enough, the Xeno left both alone.  But, the male melagris started attacking the female melagris.  I assume the male feels threatened and is asserting his dominance over the female, even though the Xeno is no threat.  After a day, the aggression lessened, and after a week, all the fish get along fine.

Conclusion

Leopard wrasses are a beautiful, peaceful addition to a reef, but they require a little bit of extra work for long-term success.

Bassleer, G., Diseases in Marine Aquarium Fish. 1996.

Gutter, Alexandra, “Fish Mucous Cocoons, the ‘mosquito nets’ of the sea,” Biology Letters, November 2010.

Zamzow, Jill, “The Physiological Ecology of UV-Absorbing Compounds from the Mucus of Marine Fishes,” 2003.

 

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