MANDARIN FISH: CHARACTERISTICS, HABITAT, FEEDING, REPRODUCTION - BIOLOGY - 2025

The Mandarin fish (Synchiropus splendidus) is a small, very colorful tropical fish belonging to the Callionymidae family. It is native to the Pacific Ocean, naturally distributed in the Philippines, Malaysia, Indonesia as well as Australia. It is a highly valued species in aquariums.

The name of the fish comes from its striking colors that resemble the tunics of the Chinese mandarins. The fish of this species have separate sexes and are of polygamous habits. In nature they are active predators that move near the bottom of coral reefs feeding on small prey.

Male mandarin fish (Synchiropus splendidus) in the Muséum Liège aquarium (Belgium). Taken and edited from: I, Luc Viatour.

It is a calm and not very territorial fish with other species, but very aggressive with those of the same species, so in aquariums you should not have more than one male to avoid continuous confrontations that end up being deadly. It can also eventually attack other species that share the same niche.

In aquariums it is demanding with the quality of the water, especially with the concentration of nitrogen compounds and the temperature. They prefer live food, but with proper training they can consume dead food.

characteristics

It is a small fish and its total length (from the tip of the snout to the distal end of the tail fin) ranges between 7 and 8 centimeters. Its shape is elongated and cylindrical, with eyes that protrude from the body. It has a small, protractile mouth, slightly advanced and armed with several rows of very fine teeth.

The body is not covered by scales, but by a foul-smelling and toxic oily film that makes it more resistant to characteristic skin diseases and possibly also protects it from potential predators.

It has two dorsal fins armed with 4 spines and 8 soft rays, respectively. The pelvic fins are adapted to facilitate their movement on the substrate. The anal fin has no spines, but 6-8 soft rays. It also has a thorn in the preopercle.

The coloration is also very characteristic and striking with a skin on a green, blue, or very rarely red background and with stripes of different colors, such as orange, blue, red and yellow. The tail fin, for its part, has blue edges on a red-orange background.

They are sexually dimorphic organisms with the female slightly smaller than the male and with less showy colors. Additionally, the first spine of the dorsal fin is much more developed in males than in females.

Taxonomy and classification

The Mandarin is a ray-finned fish (Actinopterygii) belonging to the Callionymidae family. This family contains small benthic fish distributed mainly in Indo-Pacific waters.

They bear certain similarities with the goobids, of which they differ by the protractile mouth and because the dorsal fins of the male Callionymidae are much longer than those of the goobids.

This family has 18 genera in addition to Synchiropus, which contains 44 valid species described to date. Synchiropus splendidus was described as Callionymus splendidus by the American ichthyologist Albert William Herre, in 1927, based on material collected in the Philippines, it was later relocated to the genus Synchiropus.

Habitat and distribution

Habitat

Mandarin fish are benthic, that is, they always live near the bottom. It is found at depths that range from 1 to 18 meters, at an average temperature of between 24 to 26 °. It is generally associated with coral substrates, mainly those of the branched type, forming small groups of females accompanying a single male.

Distribution

Synchiropus splendidus is a warm-water marine fish (tropical fish). It is distributed in the Indo-Pacific, Australia, the Philippines, Java and other islands of Indonesia, Solomon Islands, Japan, Malaysia, Micronesia, New Caledonia, Palau, Papua New Guinea and also in Taiwan (China).

Feeding

This fish is an active predator that feeds throughout the day, mainly on small crustaceans such as amphipods and isopods. It also feeds on polychaetes and other invertebrates, as well as protozoa. These prey are captured from rock, coral, sand or seagrass leaves using their protractile mouth.

Reproduction

Synchiropus splendidus is a polygamous species, of external fertilization. Larger males have greater reproductive success as they are more actively selected by females.

Mating occurs in the evening hours after a courtship that can be practiced by both sexes, but more frequently by males. Courtship consists of the deployment of the caudal and pectoral fin by both sexes and additionally of the dorsal fin by the male.

Then they start a dance by swimming around each other. Sometimes the male stands on the female and caresses her with his abdomen. Then both fish rise together to the surface where spawning occurs at night. Both sexes release their gametes simultaneously.

The female spawns only once per night and does so again at intervals of approximately one week and for several months, releasing up to 200 eggs at each opportunity in approximately 5 seconds.

There is no parental care for the eggs, which float freely and are dispersed by currents. Then the pairs separate and swim again to the seabed where the male will begin to look for a new partner to repeat the process, being able to mate with several females in the same day.

The time from spawning to larval settlement is only 14 days when the ideal temperature (24–26 ° C) is maintained. At that time, the larvae are active and feed on microorganisms.

Synchiropus splendidus fish on a coral reef in Indonesia. Taken and edited from: Bernard DUPONT from FRANCE.

Aquarium care

It is a gentle fish that tolerates the company of other fish very well, except in the case of male organisms of the same species. In the latter case, they are very territorial and placing two males in the same aquarium will end with the death of one of them.

If it manages to acclimatize to the aquarium it can be kept for a long time. For this, one of the essential requirements is to maintain the quality of the water in optimal conditions, since the fish does not tolerate high concentrations of nitrogenous waste, or sudden variations in temperature.

On the other hand, it is very resistant to skin diseases that normally affect other fish. This is because their skin, as already noted, lacks scales and instead has an oily film that protects it.

Aquarium

The ideal aquarium to keep a Mandarin fish in captivity should have a minimum capacity of 200 liters or 90 gallons. He must also have a place that serves as a refuge for him to hide, as he is shy in nature.

It is also essential that it be a mature aquarium with live rocks and sand with a settled population of polychaetes and other marine worms, as well as copepods and other small crustaceans, where the fish can dig for food.

Water parameters

The pH should be in the range of 8.0 to 8.4; the temperature can vary between 22 and 29 ° C, but the optimal range is more restricted and is between 24 and 27 ° C; the density should remain between 1.024 and 1.026.

Due to the fish's poor tolerance to nitrogenous waste, the water should not contain ammonium or nitrite and nitrate should not exceed 25 ppm, phosphate should also not be present, or in the worst case, should not exceed 0, 05 mg / l.

For gases, dissolved oxygen must be above 6.9 mg / l, while carbon dioxide must not be above 2.0 mg / l. The concentration ranges for calcium and magnesium are 400 to 475 and 1,200 to 1,300 mg / L, respectively.

Feeding

It is one of the main limitations in the cultivation of this species, since the Mandarin fish is a predator and in nature it only feeds on live prey. To get used to eating dead prey or flake food, a gradual replacement should be attempted, but sometimes the fish never accepts this type of food.

In the case of live food, Artemia nauplius or copepods can be supplied. It must be taken into consideration that these fish are slow in the search and capture of food, so they should not be placed together with fish of other species that compete for the same type of food.

Reproduction

It is possible to reproduce the species in captivity, but for this it is important to remember that it is a polygamous species. For reproduction to be successful, there must be a ratio of four or five females to each male.

It is also important to take into account the photoperiod, because as already noted, mating begins in the evening hours. For this species, the difficult thing is not to achieve reproduction, but rather the survival of the larvae, as they feed on very small prey and even rotifers are very large prey for these larvae.

Quarantine tank

It is important to have a tank of forty to isolate and treat diseased organisms and prevent them from infecting other members of the aquarium. It is also necessary to acclimatize new members of the community before entering the aquarium.

In the latter case, it is advisable to place each new fish in the quarantine tank for a period of 4 to 6 weeks. This should be done even if the new fish looks healthy, as it could have a latent disease, either brought in from the wild or from the stress of transport.

Additionally, these new fish could be weak from travel, so if placed directly in the aquarium, they would tend to hide to avoid harassment from other fish and could not feed well.

References

1. Synchiropus splendidus. On Wikipedia. Recovered from en.wikipedia.org.
2. Dragonet. On Wikipedia. Recovered from en.wikipedia.org.
3. Y. Sadovy, G. Mitcheson & MB Rasotto (2001). Early Development of the Mandarinfish, Synchiropus splendidus (Callionymidae), with notes on its Fishery and Potential for Culture. Aquarium Sciences and Conservation. Springer Netherlands.
4. ML Wittenrich (2010). Breeding Mandarins. In Tropical Fish Hobbits Magazine, Recovered from tfhmagazine.com.
5. Mandarin Fish: Characteristics, diet, care, aquarium and more. Recovered from hablemosdepeces.com.
6. Synchiropus splendidus (Herre, 1927). Recovered from aquanovel.com.