Mandarin Fish – A Complete Guide (Care, Diet, Facts)

The great thing about saltwater aquariums is that the choices of aquatic life are both brighter and more mesmerizing. Their vibrant colors draw aquarium hobbyists in making them extremely popular.

This remains true for the Mandarin fish, a small, brightly colored fish commonly kept in at-home saltwater aquariums. These fish do need special care in terms of their diet, but if taken care of properly, it should not be a big deal.

If you are intrigued by this unique fish, keep reading to find our complete guide down below.


About the Mandarin Fish

The Mandarin fish, otherwise known scientifically as the Synchiropus splendidus, is also referred to as the Mandarin Dragonet. It comes from the dragonet family which is scientifically called the Callionymidae family. The Mandarin fish is native to the Pacific oceans, specifically around the region of southern Australia.

They are relatively small fish, as they usually grow to around 3 inches in length. They have large pelvic fins that are used for “walking” on the floor of the body of water they are in. These are commonly mistaken as the pectoral fins, but the pectoral fins are actually transparent and near the center of their body.

Determining the sex of the Mandarin fish is simple, as the males and females have some clear differences. The female fish tend to be a little bit smaller than the male Mandarins. Also, the males tend to longer dorsal fins.

The Mandarin fish actually does not have scales. But, they are able to secrete toxins into the waters around them as a defense mechanism to divert predators.

This fish is one of the only fish that have a blue coloring. This is due to their cellular pigment which is extremely rare and unique to them. Other colors that appear on their bodies commonly include vibrant orange and green shades. Their eyes are usually a rich red color with a normal black pupil.

Their behavior is not too active or energetic. They are slow-moving fish who tend to dwell near plants and reefs. Because of their tranquil behavior, they make great community fish because they don’t really pay attention to the other fish around them.

Even though they are not categorized as a bottom-dweller fish, they do tend to spend a lot of time towards the bottom of the tank in search of food. Speaking of food, these fish are extremely picky eaters which is one of the reasons why they have a reputation for being high maintenance.

Benefits of the Mandarin Fish

Visually appealing – The vibrant colors and mesmerizing patterns are the main reason many fish owners keep the Mandarin fish in their tank. They are beautiful to look at, and they add a pop of color and contrast in any saltwater tank.

Hardy – The Mandarin fish is quite hardy and resilient when it comes to water conditions and bacteria. But, it is still highly important that you are regularly cleaning the tank and caring for your fish properly. Even though they are resilient to disease, they are still able to obtain diseases.

Friendly – The behavior of the Mandarin fish is relatively calm and tranquil, so they do not really pay much attention to other fish in community tanks. The only aggression they present is when two male Mandarin fish are placed together.

Requirements for the Mandarin Fish

Substrate – These fish love to swim by corals and rocks in their natural environment. So, you should try to recreate this effect with the substrate in your fish tank. A good substrate for the Mandarin fish would include a combination of corals and rocks. This will provide them with an area for shelter. But, before placing the rocks and corals down directly on the bottom surface of the tank, we recommend that you first place a layer of a live sand substrate because these fish do tend to dig. Also, live rocks, corals, and sands will give these fish a food source.

Water conditions – Keeping the water at the appropriate levels for the Mandarin fish is absolutely necessary for keeping them happy and healthy. The temperature of the water should remain between 75 and 81 degrees Fahrenheit which can best be accomplished with the help of an aquarium heater and aquarium thermometer. Also, the water’s pH levels should be between 8.1 and 8.4 pH, and the salinity levels should be between 1.023 and 1.025.

Filtration – Having a good filter is necessary for any aquarium no matter the size or application. So, you definitely need a resilient and effective filtration system. Mandarin fish produce a moderate amount of waste because of their eating habits. But, make sure that the flow rate on the filter is set to the lowest settings. Because of the conditions in their natural environment, they are used to slow-moving waters.

Lighting – There are not too many specifications for the lighting cycle you choose to use in a tank with a Mandarin fish. But, it is important to remember that these fish are used to normal lighting since they swim in shallow waters in the wild. The best option is to implement a natural lighting cycle that can be maintained with an aquarium light timer. An aquarium light timer is going to make sure the lights always turn on and off at the same time every day without you having to remember it. Specifically, we recommend investing in a ramp light timer which gradually turns on and off the lights to resemble a natural environment.

Tank size – A single Mandarin fish will need a tank at least the size of 30 gallons or more. This is due to their diet, not their size. They need lots of live rock in their tank because that is their main source of food. If you have two Mandarin fish, you have to double to size to 60 gallons to accommodate both fish having their own space for food. No more than two Mandarin fish should be kept in the same aquarium.

Maintaining a Mandarin Fish

In the wild, you can typically find these fish in the warmer waters. They spend their time in shallow lagoons or inshore coral reefs. This means they do not like to swim into deep waters, which translates to them needing lots of sunlight. If you can produce a tank setting that resembles their natural environment, the fish will feel more at home and stress-free.

You should be cleaning the tank regularly to avoid any bacteria or pollutants from contaminating the water. Our recommendation is that you do partial water changes every week to ensure the tank is a healthy environment for your Mandarin fish.

In terms of their health, concerning signs to look out for include a loss of appetite, swimming on their side, discoloration, darting, and rapid ventilation. These symptoms can be occurring either because of their diet or a more serious health issue.

If you think it is a diet issue, alter their diet to make sure they are getting enough nutrition to sustain a healthy lifestyle. If you think you are feeding your fish a proper diet, but they still are presenting concerning symptoms, make sure the water conditions are appropriate.

Diet for the Mandarin Fish

Mandarin fish are considered carnivores meaning they feed off of live and meat-based foods. They are notorious for being very picky eaters, so it can be difficult to have a proper and nutritious feeding routine for them.

In the wild, their diet mainly consists of small creatures that are in the shallow waters where they usually are. This includes small worms, copepods, eggs, and small snails.

You should incorporate copepod into their diet, as this is their favorite food in the wild. It is one of the few things they don’t tend to be picky about, so take advantage of that.

They do not have specific feeding times. They typically prefer to eat continuously throughout the day rather than at a specific hour. They are able to do this by feeding off of the live rock and live substrate in the tank.

You should have a good amount of live rock in your tank or else your Mandarin fish could go hungry. If you want your fish’s diet to consist of mainly live rock, you will need a tank at least 70 gallons in size that is landscaped with the live rock completely.

You should also try to incorporate other foods into their diet besides copepod and live rock. Both live and frozen shrimps have had some success with Mandarin fish. But, you must slowly introduce these foods into their diet since they are picky and skeptical of other food groups.

Tank Mates

Mandarin fish are extremely peaceful and friendly, so they will get along with a lot of other species. Ideal tank mates are fish their own size since larger fish can sometimes pick on Mandarin fish. Also, they do not do well with fish who are competitive eaters because the Mandarin does not fight for food, so they may go hungry. Therefore, you should aim to keep them with fish similar to them in size and temperament.

Some great tank mates that are compatible with the Mandarin fish are Firefish, Green Chromis, Pajama Cardinals, Royal Grammas, Clownfish, Small Damselfish, and Coral Beauties. You should be able to keep invertebrates with the Mandarin fish like some species of shrimp or snails.

You should never pair the Mandarin fish with live anemones. The Mandarin fish tend to spend a lot of their time towards the bottom of the tank. This puts them in danger if anemones are in the tank because the fish could actually be consumed by the anemone.

You should not keep more than two Mandarin fish together as they will become territorial. The worst aggression would be seen between two male Mandarin fish. If you really want to have a pair, your best bet is having one male and one female.

Breeding the Mandarin Fish

Mandarin fish can be difficult to breed when kept in captivity, but it definitely isn’t impossible.

The first step is to make sure you have a compatible mating pair. This isn’t as easy as picking a random male and female Mandarin fish, so it may take some time to find a pair that like one another.

The tank conditions for the breeding conditions need to strictly abide by the requirements listed for a regular tank housing a Mandarin fish. This is going to ensure that your fish are in a healthy environment to spawn in, and also it will provide the offspring a healthy environment to grow in.

Mandarin fish typically spawn in the nighttime. Fertilized eggs will float to the surface of the water. There can be as many as 200 eggs that are spawned at one time, and they will hatch around 12 hours after they are released.

The juveniles will start to mature in about 3 weeks after hatching. At this time, you will start to see their colors and patterns, and they will closely resemble adult Mandarins. You should wait a few weeks after that to place them with other fish in a community tank to avoid them from getting overpowered by other, more mature fish.

If you keep the conditions of the breeding tank accurate, spawning can successfully occur every few months or so.

Final Thoughts

Keeping a Mandarin fish can be an excellent opportunity to add some life and color to your tank. As long as you take care of them properly and tend to their picky eating habits, you will be thankful that you have a Mandarin.

This fish is great because it is hardy and resilient to disease and different water conditions, and they are obviously one of the most beautiful fish to look at due to their vibrant colors and brilliant designs. Also, they get along great with most other species.

Once you have learned how to take care of your Mandarin fish, you will be amazed at what an amazing asset they make in your tank.

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