Naso elegans
Naso elegans was first described by German zoologist and explorer Eduard Rüppell in 1829. This fish belongs to the family Acanthuridae, which are also known as the Surgeonfishes and Unicornfishes. The genus name Naso is derived from the Latin word “nasus,” meaning “nose,” referring to the protrusion on the nose of some species within the genus. The species name elegans is Latin for “elegant,” referring to the beautiful colors of this fish. Hence their common name Elegant Unicornfish.
Synonym: Aspisurus elegans
Description
General description:
Naso elegans has an oval-shaped, laterally flattened body. The head is dark with a broad yellow stripe above the eyes and a black snout. The flanks are gray-brown with a yellow line running from the mouth to the eye. The fins are strikingly colored: the dorsal fin is yellow with a narrow blue edge and a black submarginal band, the anal and pelvic fins are dark brown, and the caudal fin is white with black edges. This fish can reach a maximum length of 45 centimeters, although they usually stay around 35 centimeters.
Differences between sexes:
Males often have longer filaments at the tips of their caudal fins, the most obvious sign of sexual dimorphism. Behavioral differences between the sexes have not been specifically documented.
Behavior and Temperament:
Naso elegans is generally peaceful but can be aggressive towards conspecifics, especially if they are not introduced to the aquarium simultaneously. They usually live in small groups or schools, especially during the breeding season. These fish are active swimmers and need a lot of space to swim.
Life expectancy:
In the wild they can have a life expectancy of 20-30 years. In captivity, life expectancy is often shorter, depending on care and conditions.
Scalpels
Naso elegans has several striking features, including the sharp caudal spines or “scalpels” on its tail. These spines are a characteristic defense mechanism of surgeonfish, which belong to the family Acanthuridae.
Description of the Scalpels
Location and Structure :
- The caudal spines are located on either side of the cataract (the narrow part of the body just in front of the tail fin). In Naso elegans, these spines are not retractable, as in some other surgeonfish, but are permanently visible and are shaped like sharp, claw-like blades.
- The spines are bright orange, which can be a visual deterrent to potential predators.
Functie:
- These spines are used for defense. When threatened, the fish can make rapid movements to use the spines as weapons against attackers. This can cause deep cuts to other fish or even to people handling the fish.
- The striking color of the spines also serves as a warning to predators, which may discourage them from attacking.
Comparison with Other Species :
- Compared to Naso lituratus, a species often confused with Naso elegans, the spines of Naso elegans are more prominent and brightly colored. This difference helps in identifying the species.
Behavior and Use
- Defense mechanism: The spines are mainly used as a defense mechanism. When the fish feels threatened, it can move its tail quickly to use the spines against the attacker.
- Visual Defense: The bright orange color of the spines serves as a visual warning to potential predators, which may discourage them from attacking.
The caudal spines of the Naso elegans are a key part of their defense mechanism. They are bright orange and permanently visible, distinguishing them from some other surgeonfish that have retractable spines. These spines serve as both physical weapons and visual deterrents to predators.
Biotope
Naso elegans is found in the Indian and western Pacific Oceans, including the Red Sea, along the eastern coast of Africa to Durban, South Africa, and east to Bali, Indonesia. They inhabit coral reefs and lagoons, often at depths of 5 to 30 meters. Their natural habitats are coral and rock formations where they feed on algae. They have no specific natural predators documented, but they use their sharp caudal spines for defense.
Diet
In the wild:
Naso elegans feeds mainly on benthic algae, especially brown algae such as Dictyota and Sargassum.
In the aquarium:
In the aquarium they should be fed a diet rich in algae, such as nori and spirulina, supplemented with small crustaceans such as krill, mysis and artemia. It is important not to give them too much animal food, as this can cause digestive problems.
Reefsafe:
Yes, Naso elegans is reefsafe and will not eat coral, polyps or shrimp.
The Aquarium
Aquarium size:
The minimum volume for an aquarium in which Naso elegans is kept is 1,000 liters. For multiple specimens, an even larger aquarium is needed to prevent territorial conflicts.
Aquarium Setup:
The aquarium should be set up with plenty of swimming space and sufficient hiding places, such as coral and rock formations. A sand or fine gravel substrate is most suitable.
Water parameters:
The ideal water parameters are a temperature between 22°C and 26°C, a pH between 8.2 and 8.4, and good water circulation.
Introduction to the aquarium:
It is best to introduce Naso elegans to the aquarium only after it has matured well and has grown sufficient algae
Compatibility:
Naso elegans can live well with other peaceful reef fish such as Clownfish, Surgeonfish, and Wrasse. However, they should not be kept with aggressive or territorial species.
Breeding Naso elegans
There are no specific data available on breeding Naso elegans in an aquarium. It is generally considered that they are difficult to breed in captivity due to their specific breeding behavior and the large space they require.
In the wild, they are believed to spawn in groups, with the eggs being pelagic and dispersed by currents. The larvae have a pelagic stage that lasts about two months before settling on reefs.
Particularities
Naso elegans has the ability to rapidly change color depending on their mood or environment, thanks to the presence of chromatophores. They are also known for their sharp caudal spines that they use for defense.
Conclusion
Naso elegans is a beautiful and interesting fish species that is suitable for advanced aquarists due to their specific dietary and space requirements. They are peaceful but can be aggressive towards conspecifics if not introduced at the same time. Keeping this fish requires a large and well-equipped aquarium with plenty of algae and hiding places.
Although difficult to breed in captivity, they make a fascinating addition to any large marine aquarium. Their ability to change color and their unique appearance make them a beloved species among experienced aquarists.
Video
Author
John de Lange
Copyright images
