Amphiprion chrysogaster – Mauritian Anemonefish
Amphiprion chrysogaster was first described by Georges Cuvier in 1830. This fish belongs to the family Pomacentridae, which is known as the family of anemonefish and damselfish. The genus name Amphiprion is derived from Greek, where “amphi” means “on both sides” and “prion” means “saw.” This possibly refers to the saw-like structure of the gill covers or fins of these fish. The species name chrysogaster is composed of the Greek words “chryso” meaning “gold” and “gaster” meaning “belly,” referring to the gold-like color of the belly of the fish within this genus.
Synonyms: Amphiprion fusciventer, Amphiprion mauritiensis.
Description
Appearance of Amphiprion chrysogaster
The Mauritian Anemonefish has a distinctive appearance characteristic of anemone fish. The body of this fish is oval in shape and exhibits a robust build. Adults are predominantly dark brown to nearly black in color, with three prominent white stripes running down the body. The snout and breast are orange, while the caudal fin is black or dark brown, often with a white border. The fins are generally dark, with the pectoral and ventral fins that may have a yellow tinge. This fish can reach a maximum length of about 14 to 15 centimeters.
Differences between Males and Females
In Amphiprion chrysogaster, females tend to be larger than males. There is sexual dichromatism, in which the snout of the male is a dull yellow color, while that of the female is bright yellow. Behaviorally, the females are more dominant, and if the dominant female dies, the largest male will change sex and take over the female’s role.
Differences between Juveniles and Adults
Juvenile Amphiprion chrysogaster are often brighter in color, with an orange body and white stripes. As they age, their color changes depending on the anemone in which they live; for example, in more toxic anemones they may take on a darker color.
Behavior and Temperament
The Mauritian Anemonefish is generally peaceful, but can become territorial, especially when inhabiting an anemone. They usually live in pairs or small groups, with the largest and most dominant fish assuming the female role. These fish are not shy and exhibit a symbiotic relationship with sea anemones, offering protection to the anemone in exchange for food and shelter. They are found mainly in the middle waters of lagoons and coral reefs.
Life expectancy
In the wild, Amphiprion chrysogaster fish can live up to 15 years. In aquariums, if properly cared for, they can reach a similar lifespan.
Social Structure and Gender Change
Like other anemone fish, Amphiprion chrysogaster are protandrous hermaphrodites, meaning they begin life as males and later change sex to females, if necessary. In a social group, the largest and most dominant fish is a female, and if she dies, the largest male will change sex to take her place.
Symbiosis between Amphiprion chrysogaster and Sea Anemones
The Mauritian Anemonefish lives in a symbiotic relationship with sea anemones, a fascinating example of mutualism in nature. In this relationship, the sea anemone provides protection to the anemonefish from predators through its stinging cells, which contain toxins. These stinging cells are capable of paralyzing or deterring prey, but the anemone fish is an exception.
Protection against Nettle Cells
The anemone fish has a unique adaptation that protects it from the nettle cells of the anemone. This is due to a layer of mucus on the fish’s skin, which has a chemical composition similar to that of the anemone itself. As a result, the anemone does not recognize the fish as a foreign intruder, but as a part of itself, so the stinging cells are not activated.
Benefits of the Symbiosis
For the anemone fish, the symbiosis provides protection from predators and access to food scraps left behind by the anemone. In return, the anemone fish protects the anemone from its natural enemies and removes parasites from the anemone. These mutual benefits make the symbiosis between the anemone fish and the sea anemone a successful and lasting partnership.
This symbiotic relationship is a wonderful example of how species can adapt and cooperate to survive in their natural habitat.
Biotope
Natural Distribution and Ecosystem
The Mauritian Anemonefish is endemic to the waters around Mauritius and probably Reunion. This fish species is found mainly in the lagoons and outer reefs of the western Indian Ocean. They live in symbiosis with several species of sea anemones, such as Heteractis magnifica, Stichodactyla haddoni, and Stichodactyla mertensii.
Natural Habitat
The natural habitat of Amphiprion chrysogaster consists of coral reefs and lagoons, where they often live near sea anemones. This environment is rich in coral and rocks, which provide hiding places for the fish and their symbiotic anemones. The bottom of their habitat usually consists of sand, rocks and coral.
Natural Enemies and Food Chain
In their natural environment, Amphiprion chrysogaster fish have few natural enemies, thanks to their symbiotic relationship with sea anemones. The anemones provide protection from predators through their venomous tentacles. The fish themselves are omnivores and feed on planktonic crustaceans such as copepods, mysis, and shrimp larvae, as well as algae. They are not active hunters, but rather opportunistic eaters who feed on what is available in their environment.
Diet
Diet in the Wild
Amphiprion chrysogaster feeds in the wild mainly on planktonic crustaceans such as copepods, mysis, and shrimp larvae. They also consume algae found in their environment. These omnivorous eating habits allow them to survive in the diverse ecosystems of coral reefs and lagoons.
Food in the Aquarium
In an aquarium environment, it is important to offer a varied diet that mimics the natural feeding habits of the Amphiprion chrysogaster. They can be fed a mix of live and frozen foods such as artemia, mysis, and krill. They can also eat dry foods such as flakes and pellets, especially those enriched with spirulina. It is recommended to give several small meals a day rather than one large meal.
Reefsafe
The Mauritian Anemonefish is generally reefsafe, meaning they do not eat coral, polyps or shrimp. They live symbiotically with sea anemones and are not prone to harming other reef inhabitants. This makes them a suitable choice for reef aquariums, provided they are kept with compatible species.
The Aquarium
Aquarium size
To keep Amphiprion chrysogaster, an aquarium of at least 200 liters is recommended. If you want to keep several pairs, the aquarium should be considerably larger, preferably more than 300 liters, to provide sufficient territory and hiding places.
The Aquarium
The aquarium should be decorated with live rock and coral to mimic a natural environment. This provides hiding places and helps maintain water quality. The best substrate is fine sand, which mimics the fish’s natural environment and is suitable for symbiotic anemones.
Water parameters
The ideal water conditions for Amphiprion chrysogaster in the aquarium are a temperature between 22°C and 28°C, a pH of 8.2 to 8.4, and a salinity (specific weight) of 1,020 to 1,026. It is important to keep nitrate levels below 50 mg/L.
Introduction to the Aquarium
It is recommended to introduce this fish species into the aquarium only after it has matured properly. This means that the aquarium should already be running for several weeks, allowing algae and other microorganisms to establish themselves, contributing to a stable environment.
Suitable Tank Mates
The Mauritian Anemonefish can live well with other peaceful reef fish. Suitable species include gobies, blennies, and other Anemonefish such as Amphiprion ocellaris and Amphiprion percula. It is important to avoid aggressive or highly territorial species, as these can intimidate the anemone fish.
Breeding aquarium and conditioning
Breeding Tank
The Mauritian Anemonefish has been successfully bred in both ordinary aquariums and in specially designed breeding aquariums. In the context of the breeding programs conducted, the fish were often kept in specially designed breeding aquariums to provide optimal conditions for reproduction.
Special Breeding Aquarium:
- Size: Breeding aquariums varied in size, but a common size was a 100- to 200-liter aquarium.
- Water Quality: The water was filtered with a biological filtration system and the water circulation was carefully controlled to maintain a stable environment.
- Lighting: Muted lighting was used to mimic a natural environment and minimize stress on the fish.
- Filter: A biological filtration system was used to maintain water quality and protect eggs and larvae from contaminants.
Conditioning the Fish
To condition the fish , they were fed a diet of high-quality protein sources such as chopped clam meat and other marine foods. This diet helped promote the health and fertility of the fish.
Sex ratio
In breeding groups, a ratio of one female to several males was often maintained. In that case, the largest male mates with the female.
The Spawn
Colors during spawning
During mating, the colors of Amphiprion chrysogaster often become more intense. The snout of the male may take on a dull yellow color, while that of the female is bright yellow. This color change may be part of the courting ritual and serves to attract the partner’s attention.
Courting Ritual
The courting ritual of the Amphiprion chrysogaster begins with cleaning the substrate where the eggs will be laid. The fish exhibit behaviors such as biting and pushing against each other, which is part of their mating ritual. This behavior may begin several days before the actual mating.
Substrate for Eggs
The eggs are usually deposited on hard surfaces such as small earthenware pots, granite stones, or even the PVC pipes of the biological filtration system in the aquarium. This provides a stable base for the eggs to attach to.
Time of spawning
Spawning usually takes place in the morning to early afternoon, between 09:00 and 14: 00. This time may vary depending on the specific conditions in the aquarium.
Eggs and Laying Method
The Mauritian Anemonefish is an oviparous species, meaning they lay eggs that develop outside the body. The eggs are laid openly on the substrate and are not protected by a cave or other structure. The number of eggs per clutch ranges from 300 to 800. The eggs are capsule-shaped, measuring about 1.7 to 2.9 mm in length, and have a bright orange color when laid. As the eggs develop, they change color to dark brown and eventually silvery, reflecting the color of the larvae’s eyes.
Raising the fry
Hatching the Eggs
The eggs of the Amphiprion chrysogaster hatch after a period of 6 to 7 days. During this period, the eggs are guarded and ventilated by the parents with their fins and mouths. Egg hatching usually occurs at night, peaking between 7 p.m. and 10 p.m.
Free Swimming and Parent Care
After hatching, the larvae begin to swim freely. The parents, particularly the male, continue to monitor and ventilate the eggs until they hatch. There is no specific mention of parental supervision after the young begin to swim freely, but parental care appears to be focused primarily on the eggs until hatching.
First Food for the Fry
The young larvae are fed on rotifer Brachionus rotundiformis during the first four days after hatching. From the fifth day they are fed with a mixture of Brachionus rotundiformis and freshly hatched Artemia nauplii. It is important to make sure there are no unopened Artemia cysts in the food, as this can be harmful to the larvae.
Water Changes and Survival Rate
The water in the larval rearing tanks is continuously filtered and changed to maintain a healthy environment. The survival rate of the larvae during the critical period (from hatching to the fifth day) ranges from 50% to 60%. After this period, and with proper care, the larvae can develop into juveniles within 12 to 15 days after hatching.
Particularities
Endemic distribution
Amphiprion chrysogaster is endemic to the Mascareignes Islands, particularly Mauritius and Reunion. This means that they do not occur in the wild anywhere else in the world, which gives them a unique place in the biodiversity of this region.
Color change
A remarkable feature of Amphiprion chrysogaster is their ability to change color depending on the anemone in which they live. When living in a Heteractis magnifica, their orange body can darken to brown. In more toxic anemones such as those of the genus Stichodactyla, their bodies may even turn black. This color change may be related to the fish’s stress response to the anemone’s toxicity.
Rarity in Commerce
Although Amphiprion chrysogaster is an attractive species for aquariums, they are a relative rarity in the trade due to their limited geographic distribution. This makes them a desirable species for aquarists looking for unique and less common species.
Conclusion
The Mauritian Anemonefish is a fascinating species that can appeal to beginners and experienced aquarists alike. They are relatively easy to keep in a well-maintained aquarium of at least 200 liters, with a stable environment and suitable water values. Their symbiotic relationship with sea anemones makes them particularly interesting, although they can also thrive without an anemone.
These fish exhibit unique behaviors such as color change depending on their anemone and sex change within their social structure. Although they are generally peaceful, they can become territorial, especially in the presence of an anemone. With proper care and attention, they can be a valuable addition to a reef aquarium, with their interesting behavior and vivid colors providing an engaging viewing experience.
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Author
John de Lange
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