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Kidadl Team

AUGUST 06, 2021

19 Bluespine Unicornfish Facts You’ll Never Forget

Bluespine unicornfish facts talk about the habitat of this fish.

If you are on the search for different fish that are unique in their physical appearance, then look no further than the bluespine unicornfish or the Naso unicornis. Belonging to the genus Naso, these fish are often identified by the small horns on top of their heads. Although there hasn't been any concrete reason presented as to why these fishes have these horns, they look really cool on them! The bluespine unicornfish is one of the most abundant fish in the world, with its distribution ranging from east African seas to the Indian Ocean and the Pacific Ocean. They are mostly seen dwelling within coral reefs and they need strong water currents in order to survive. In recent years, many people have been keeping these calm fish in their aquariums with great success as they are quite easy to care for.

Read on to learn more facts about the bluespine unicornfish. If you want to learn about other fish, take a look at these spiny dogfish and catfish facts too.

Bluespine Unicornfish Interesting Facts

What type of animal is a bluespine unicornfish?

The bluespine unicornfish (Naso unicornis) is a type of fish that is characterized by a blue spinal plate on each side of the caudal peduncle (tail). Along with this, the unicorn-like horn on their head is also a distinct feature of the bluespine unicornfish. Horned fish such as this species are closely related to species of surgeonfish and tang fish.

What class of animal does a bluespine unicornfish belong to?

Bluespine unicornfish are a species of fish that belong to the class of Actinopterygii or ray-finned fishes. These fish are part of the Acanthuridae family which also houses species of tangs and surgeonfish. A common characteristic of Acanthuridae fish is that all fish belonging to this family have sharp blades around the base of their tails. The scientific name of this fish is Naso unicornis, as they belong to the genus Naso.

How many bluespine unicornfish are there in the world?

While the distribution of the bluespine unicornfish is quite diverse, these fish are at risk of being caught by fishermen as they are a source of food. However, despite this, bluespine unicornfish have had an abundant population in their marine range in the Indo-Pacific and in the Red Sea. Although current trends and the total population are unknown, there are many signs that tell us that these fish are not experiencing a decline in their population.

Where does a bluespine unicornfish live?

These fish are usually found near sea lagoons, coral reefs, and tropical waters. As such, their marine distribution range is quite diverse. They are found in the Indo-Pacific marine waters of Japan, Australia, China, India, Guam, and other countries. Their distribution range stretches as far as east Africa and the Red Sea. They are quite famous in the US state of Hawaii and are also spotted near island nations of the south-eastern, south-western, and central Pacific. Due to their unique appearance and largely easy-to-maintain lifestyle, this unicorn fish species is quickly becoming a popular choice for aquarium owners too. They are peaceful aquarium fish. However, they can be difficult to acquire in the aquarium trade.

What is a bluespine unicornfish's habitat?

The bluespine unicornfish (Naso unicornis) has a marine habitat that is found in coral reefs. They are found mostly near inland coral reef areas and can be easily spotted in coral reef areas around coastlines. The coral reef area, along with moats and lagoons where they are found, must have strong water movements and currents. This is contrasted with the needs of juveniles of the species that usually live in the shallow waters of ports and harbors. They mainly inhabitant marine waters that have a temperature of 77-85 F (25-29.4 C). This species is not really considered to be the one that swims at great depths with their average sea depth being 16-263 ft (4.9-80.2 m). However, there are Most scientists agree that they usually prefer to live at an optimal depth of around 33 ft (10 m). Since, their diet and feeding depend on the leafy, brown algae found along the reef, they are most easily spotted there. This unicorn fish variant is mainly diurnal in nature.

Who do bluespine unicornfish live with?

Despite the bluespine unicornfish not being too social, it is not alien to the concept of a group. They are often seen swimming around in small groups or schools while in search of food. There are exceptions to this as sometimes this small group can turn into a large school. However, the foraging group usually remains small in size. Apart from this, you can find males to be solitary on some occasions.

How long does a bluespine unicornfish live?

There are various reports about the lifespan of these unicorn fish, yet most agree that they easily live to the age of 30 years in the sea. This may rise up to as much as 50 years too. Interestingly, there are research papers that suggest that this fish species may live for a little less time in captivity when kept in an aquarium or a tank. This may be down to species missing their natural reef habitat and marine waters. The oldest reported age of this fish was 55 years, which is slightly more than the average age of some species of tilefish.

How do they reproduce?

Males are known to engage in courtship rituals that help them attract females in a group or school. These displays often include changes in the color of their dorsal, caudal (tail), and anal fins and their body. Their horn will also change color when they are courting females and when engaging in fights with other males. There have been reports that a male fish may spawn with several females in this species. These Pacific fish are known to partake in pair spawning by coming up to the sea surface and releasing their eggs in water. These eggs are known as pelagic larvae. While the total number of eggs laid by this species at a time has not been estimated,  using data from other related fish like the blue tang, we can assume that they lay over 40,000 eggs.

What is their conservation status?

Many aquarium fish are not evaluated by the International Union For Conservation Of Nature. However, despite being now seen as an aquarium species, the tropical bluespine unicornfish (Naso unicornis) has been evaluated and has been placed in the category of Least Concern by the IUCN. This is a reflection of the fact that the number of fish of this species along coastal reefs shows no sign of decline. They are not endangered.

Bluespine Unicornfish Fun Facts

What do bluespine unicornfish look like?

Bluespine unicornfish are marine animals with a distinct appearance in regards to their body and fins. They have a narrow caudal peduncle (tail). Two knife-like spines are located on each side of the caudal peduncle (tail). These spines on the tail are blue in color and that is how the species derived its name. Along with the spines on the caudal peduncle, there are spines on the dorsal and anal fins. These dorsal and anal fins have thin yellowish-blue lines on them. The overall coloration of this fish with a horn is greenish-gray, not blue. Speaking of the horn, it is a structure that starts to grow when these fish are around 5 in (12.7 cm) long. Males have more prominent colors and their horn is also more pronounced than females. The horn does not grow too much, in fact, the horn on their forehead never goes past their snout. There has been no scientific reason established as to why this tropical fish has this horn.

Bluespine unicornfishes have horns on their foreheads.

How cute are they?

These fish, with their blue highlights on their greenish-gray body, are quite beautiful to look at. They are also known to have a calm temperament and are perfect aquarium fishes. This adds to the cuteness of the species, with many people finding these animals adorable and cute.

How do they communicate?

They stay near coastal reefs to feed on leafy, brown algae together but the modes of communication between fish of this species are not really known. They may be using different auditory and visual cues to relay certain messages. We know that when this marine animal breeds, it exhibits visual cues like changing the colors of their blue-highlighted scales and greenish-gray bodies while courting or fighting against other fish.

How big is a bluespine unicornfish?

In general, the length of the bluespine unicornfish (Naso unicornis) generally averages a length of around 27.5 in (70 cm). However, this fish can grow to more than 27.5 in (70 cm) long sometimes. In comparison, the convict cichlid is almost four times the size of this tropical marine animal!

How fast can a bluespine unicornfish move?

Although the exact speed of this reef-dwelling species is not known, they are known to be quite fast in the water even though they are not the top predators in their ecosystem.

How much does a bluespine unicornfish weigh?

The weight of these herbivorous fishes is related to their diet. The average weight of the bluespine unicornfish is around 3.2 lb (1451.5 gm) but it can be much less.

What are the male and female names of the species?

There are no distinct names for male and female fish of this reef-dwelling fish species.

What would you call a baby bluespine unicornfish?

Like most fish, young unicornfish are initially known as fry and then can be referred to as juveniles.

What do they eat?

Being herbivore fish, bluespine fish search for their food amongst coral reefs. They have a diet that consists of feeding on algae. These fish will often roam around in groups as they forage algae along the reef lines. Apart from algae, when these fish are housed in a large aquarium, you can feed them fish pellets.

Are they poisonous?

No, these fish are not poisonous in nature. However, undercooking these fish makes them dangerous for human consumption.

Would they make a good pet?

Bluespine unicornfish are marine animals by nature. They are seen inhabiting reef areas that have strong currents in the water but they can also be kept as pets. If you are taking this fish as a pet, there are certain conditions that you have to follow. Firstly, a large aquarium tank that can house the specimen is required. There must be strong artificial currents or a strong flow in the water that mimics their native reef habitat. Once the fish have warmed up to their new home, you'll find out that they have a cool and calm temperament and are compatible with other fish like clownfish and gobies. However, the Acanthuridae group of fish can be very territorial sometimes, so there might be a problem if you place another unicornfish in the same aquarium.

Did you know...

These reef-dwelling fish, also known as the unicorn tang, have a growth rate of around 4.4 in (11.2 cm) per year. They reach almost 80% of their total length within the first five years of their life.

Why are they called bluespine unicornfish?

This specific unicornfish is known as the 'bluespine' due to the blue coloration on the spines on each side of the caudal base. The name 'unicornfish' comes from the horn on their head that resembles a unicorn's horn.

Are they reef safe?

Of course, these are reef-safe fish as their marine habitats primarily consist of coastal reefs.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other fish from our Swai fish facts and skate fish facts pages.

You can even occupy yourself at home by coloring in one of our free printable bluespine unicornfish coloring pages.

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