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The Mandarin Goby is a very popular and peaceful fish in the saltwater world because of its highly visual and cool colors.

Despite its popularity there is some confusion and misinformation about how to care for them.  Read this guide and learn more about this species!

Species Summary

The Mandarin Goby fish, known scientifically as Synchiropus splendidus, is native to the warm Pacific waters between Japan and Australia. Sometimes called mandarinfish or dragonets, they belong to the Callionymidae family. These fish populate sandy lagoons and coral reefs, enjoying warm shallow water and abundant food supplies.

Despite their vivid coloration, the fish is difficult to spot in the wild because it’s a small bottom dweller, adapted to hiding among the rocks and coral. Many saltwater aquarists love the Mandarin Goby due to its coloration and longevity.

Gobies are an active yet slow-moving species, devoting their time to scouring their habitat for food. They have two large pelvic fins they use to “crawl” along the seafloor while searching for food. Interestingly, gobies are one of only two vertebrate species with blue coloring. They are best suited for experienced aquarists with well-established tanks due to the fish’s dietary needs and space requirements.

When selecting your Mandarin Goby, ask the retailer if the fish was wild-caught or raised in a tank. Feeding wild gobies is challenging for even the most skilled owners because the fish sometimes rejects frozen or bottled food. Tank-raised fish will have a smoother adjustment to your home tank because they are already conditioned to the simulated diet you will provide.

Appearance

The Mandarin Goby’s popularity is largely due to its distinctive markings and coloring. The saltwater fish features striking color patterns, gaining its name from the resemblance to the dazzling robes of Chinese Imperial Mandarin.

These fish are scaleless, adding to the smoothness of their appearance. Gobies’ bodies are blue due to their light-reflecting cyanophore cells. Typically, the fish have either a green, red, or psychedelic pattern to their dorsal and pectoral fins.

Males have a taller dorsal fin than females that features a stunning orange and blue pattern. In addition, the male fin has a long spike extending out. Psychedelic mandarins have pale grayish-green coloring accented by black, pink, and blue spots.

Their eyes are in constant motion and resemble an amphibian’s eyes more than those typically observed in fish. They are usually red with black pupils.

Gobies have multiple protrusions and spikes that emerge from their cheeks. Their true pectoral fins are translucent and difficult to spot. Due to their small size and the delicacy of their anatomy, you should never use a net to catch the fish. When transferring or quarantining your goby, scoop it out using a sterile container to minimize the risk of damaging its delicate protrusions.

Changes in appearance are an excellent way to spot the early signs of disease or poor water conditions but practice caution. The coloring of males is more vivid than females. In addition, gobies burrow in the sand. Your fish’s faded appearance may simply result from sand residue obscuring its gorgeous appearance.

Lifespan

A Mandarin Goby lifespan in captivity can be two to four years.  In the wild it could go as high as 15 years. The main challenge is ensuring the fish eats once you introduce it to your tank. The Mandarin Goby is a particular eater since the store-raised gobies only accept live, bottled, or frozen and thawed food whereas the wild one does not accept thawed food. 

Generally, these hardy fish will thrive for years if they make it through the first few weeks in your tank. Be sure to monitor its eating habits closely.

Average Size

The Mandarin Goby’s size can be up to 3 inches long in adulthood. They are relatively shy and slow-moving fish that love to hide and patrol your tank’s rocks, looking for food and hiding places. Males are noticeably larger than females.

Mandarin Goby Care

Mandarin Goby care requires an advanced level of care, since these are tropical saltwater fish with a narrow diet. Fortunately, standard reef parameters allow them to thrive. Experts recommend only introducing gobies to well-established tanks with live rock and sand. These conditions best simulate the natural environment and allow the microorganisms your goby craves to flourish.

Tank Size

Your Mandarin Goby requires a tank size of 30-gallons or more.This volume allows the fish adequate room to roam the aquarium floor and enough space for its food to populate. Gobies cannot function in small tanks because they lack enough hiding spots. The fish’s stress level will rise without adequate space, making them vulnerable to disease.

Author Note: While 30 gallons is the minimum, most experienced aquarists recommend 50 gallons or larger for ideal conditions. This volume is essential if you plan to have multiple species of fish. A pair of gobies require a 75-gallon or larger tank. The main challenge with a smaller tank is keeping your fish calm and well-fed.

Water Parameters

Establishing standard saltwater reef conditions will keep your Mandarin Goby happy and healthy. This slow-moving fish essentially grazes for its food. Water flow should be slow to moderate, allowing your fish to explore the aquarium base and eat at its leisure.

Completing a 10% water change every two weeks and a monthly 25% water change will promote optimal conditions for your goby and prevent disease due to immune system compromise. Increase the volume and frequency of your water changes for larger or heavily populated tanks.

• Water temperature: The tank should be between 74° and 80°F. It’s essential that the temperature not fluctuate more than 2° F in 24 hours.
• Water pH levels: pH must be maintained between 7.9 and 8.4. Check the levels weekly because pH outside the approved range compromises your goby’s immune system.
• Water hardness: Maintain the tank’s carbonate hardness between 8 to 12 dKH. These levels are necessary for the survival of your fish and the microorganisms living in the rock and sand.
• Specific gravity: Salinity is best between 1.022 to 1.025 sg. The level should not change by more than .001 sg in 24 hours.

What To Put In Their Tank

It’s best to populate your tank with material that simulates reef conditions because they give your Mandarin Goby options for hiding spots. Mimicking their natural habitat will minimize stress on your fish, otherwise the stress can lead to disease or death.

Gobies thrive in tanks filled with live rock and sand because these conditions create a prime habitat for their primary food source. Experts advise that you should only introduce gobies to a mature tank, ideally one that has been operational for over eight months. Aim for a minimum of 75 pounds of living rock, but be careful not to overcrowd the tank. While the goby needs room to hide, you do not want to make the conditions too dense.

The goby buries itself in the sand to sleep as part of its natural defensive impulse. The living-sand substrate should be at least two inches thick and consist of 1 to 2 mm grain sand.

As well-adapted bottom dwellers, their eyes function well in dimmer light. Standard tank lights are acceptable. Avoid anything brighter because it could harm the fish and impede their ability to hunt for food. Providing light for nine to 14 hours per day will promote optimal algae growth and establish a consistent day-night cycle for your fish.

Author Note: Feel free to add artificial decorative structures like caves or plants. These materials will add to the tank’s visual diversity and give your Mandarin Goby more to explore. Opt for smooth or rounded objects rather than ones with sharp edges. Your goby’s movements around sharp edges could damage its delicate spikes and protrusions.

Common Possible Diseases

Like other scaleless species, gobies are relatively resilient and resist many diseases. They secrete a bitter mucus that deters predators in the wild. Captive fish enjoy an added layer of immune protection thanks to this natural defense mechanism.

However, gobies are vulnerable to the same diseases that affect other reef fish. In many cases, improving water quality and managing the fish’s stress level can resolve many health conditions.

Marine ich, characterized by cysts on the gills, fins, or skin, requires immediate quarantine to rid the fish of parasites. You’ll also need to fully replace the tank water.

Reddening of the skin, cloudy eyes, open sores, and growths across the fins and body indicate viral and bacterial infections. Consult an aquatic veterinarian before administering medication because many substances can alter your tank’s pH and hardness. Remember to quarantine your new goby before introducing it to your tank.

Food & Diet

The Mandarin Goby is a picky carnivorous eaters, making it essential to purchase a fish bred in captivity rather than a wild-caught one, which often refuses to eat food provided in their tanks. All gobies have a high metabolism. They continually eat as they explore the tank and rocks.

Author Note: Your fish will eat amphipods, ostracods, polychaete worms, artemiacyclops, protozoans, gastropods, Mysis shrimp, and other microorganisms. Their preferred food is copepods, tiny crustaceans.

Keeping your goby nourished requires a stable colony of copepods, which is another reason you need a 30-gallon or larger tank. The copepods need adequate space to hide and breed. Otherwise, your relentless goby will deplete the entire population.

Placing a copepod breeding box in your tank or growing copepods in a separate tank can help ensure a steady food supply. Copepods are also sensitive to temperature fluctuations, making it even more important to maintain a consistent temperature between 74° and 80°F.

If you elect to feed your fish rather than populating the tank with copepods, provide small portions two to three times per day. Only supply enough food that will take the fish one to two minutes to eat.

You can purchase live copepods for about $25 per bottle. Depending on its size, your goby will consume approximately one bottle per month. Frozen shrimp or other crustaceans are also options. They must be thawed before serving.

If your tank includes companion fish, verify whether their diets and your Mandarin Goby’s overlap. If multiple fish share a diet, adjust your copepod population accordingly or closely monitor your feedings to ensure each fish receives proper nourishment.

Behavior & Temperament

Your Mandarin Goby will seem like a perpetual motion machine. It will constantly search the floor of its tank for delicious microorganisms to keep itself going. As reef-adapted fish, gobies will explore whatever you place in the tank, scouring every cranny for food and shelter. Fortunately, their dazzling color patterns make them easy to spot in your tank.

Despite their eye-catching appearance, Mandarin Gobies are shy and mellow. They are not aggressive toward other fish and are used to the hustle and bustle of a coral reef. Gobies take time to adjust to new tank inhabitants. Monitor interactions closely when introducing companions.

Tank Mates

Your goby should not share a tank with significantly larger or aggressive fish, including angels, tangs, and wrasses. Gobies are relatively docile and won’t successfully compete for food. Conflict could lead to starvation as your fish spends most of its time hiding among the rocks.

The goby’s toxic mucus layer protects it from harassment by other fish. The only active threats are anemones and scorpion fish.

Suitable Mandarin Goby tank mates are: 

• Coral Beauty
• Firefish
• Pajama Cardinal
• Clownfish
• Green Chromis
• Royal Gramma
• Seahorse
• Watchman Goby
• Small Damselfish
• Smaller marine shrimps, snails, and crabs

Author Note: When choosing companions, remember that you must have a large enough tank and enough available food to maintain the population. Introduce new fish slowly and monitor for behavioral and dietary changes in your goby.

Gobies are highly territorial toward members of their species. Two males will fight, possibly to the death. It’s best to keep a single goby or a male/female pair.

Breeding

Mandarin Goby pairs can breed once a week year-round with proper tank conditions, but females are selective. The male goby makes a mating show and must draw the female goby into a “dance” in which each fish releases their reproductive material.

Simply housing a pair together does not guarantee they will breed. Matched pairs are sold, but they are generally expensive and scarce.

The main challenge with breeding gobies is to isolate and protect the young from other fish. A breeding box or separate tank is ideal for isolating the planktonic larvae and nurturing the fish to maturity.

Wrapping Up

If you were interested in this fish before, we hope this guide encourages you to give it a chance. Due to its unique color and fun behavior, there’s a lot to like about this species!

Despite their nature as picky eaters, it won’t be hard to figure out a good routine and diet. All it takes is a little work. We hope you found this guide helpful and wish you luck on your journey!