Lopez's Unicornfish ~ Slender UnicornfishFamily: AcanthuridaeNaso lopeziPhoto © Animal-World: Courtesy courtesy: Melissa
Though still quite rare, the Elongate Unicornfish or Lopez's Unicornfish is becoming a bit more common in pet stores. The fish seen in the picture above has been keep for over six years!
True to its name, the Elongate Unicornfish has a noticeably more slender or elongated body shape than most of the species in the Naso genera. It is quite a lively elegant swimmer with this streamlined form. Though it is a 'unicornfish', neither the male nor the female will grow a horn. It is very beautiful with a delicate pattern formed by many small spots. Like all of the unicornfish it has the ability to quickly and dramatically change its color from pale to brilliant to dark, depending on mood or environment. Being a very big fish that will reach a length of just under 2 feet in length, this pretty specimen is most suitable for a large show aquarium.
All the species in the Naso genus are peaceful fish, and the Elongate Unicornfish is no exception. It will get along with most other marine fish and can be kept with a variety of tank mates including other genus' of surgeonfish. However unless you have a huge (hundreds of gallons) system, it is best to house just one Naso tang to a tank. Being an herbivore it is a good algae eater, but is also a large energetic fish and may topple corals while swimming about in fast clips.
The Elongate Unicornfish or Lopez's Unicornfish requires a lot of water turbulence highly saturated with oxygen rather than a placid aquarium. Being very active during the day they need a large tank with plenty of room to swim, but will also need some rocks/ corals to provide some cover and to sleep in at night. They are primarily herbivores and an aquarium with natural algae growth will be greatly appreciated. Once they get acclimated and become accustom to aquarium foods they are quite hardy.
For more Information on keeping marine fish see:
Guide to a Happy, Healthy Marine Aquarium
Habitat: Natural geographic location: The Elongate Unicornfish or Lopez's Unicornfish was described by Herre in 1927. They are found widespread throughout the Western Pacific; southern Honshu, Japan to the Great Barrier Reef and New Caledonia, Similan Islands in the Andaman Sea and Guam, and recently from Tonga.
In their natural habitat they are usually found at depths between 20 - 65 feet (6 - 20 meters) but have been reported as deep as 98 feet (30 meters). They occur singly, in small groups, and occasionally form large schools. They inhabit coastal to outer reef slopes with strong currents. Naso species will stay within 32 to 65 feet (10 - 20 meters) of the reef where they can quickly retreat if necessary.
Description: The Elongate Unicornfish or Lopez's Unicornfish, as its common name indicates is quite slender. Like the other Naso species, this elongated body shape and a narrow caudal peduncle are features that distinguish this genus from other Acanthurids. Though it is a 'unicornfish', neither the male nor the female will grow a horn.
Adults generally have an iridescent grayish-blue body color that becomes paler on the lower half. The upper half of the body and head have numerous small round dark spots. Like all of the unicornfish it has the ability to quickly and dramatically change its color from pale to brilliant to dark, depending on mood or environment. The body can be nearly black, sometimes a dark violet, or a pearl gray. The spots can be turquoise to dark gray and the head can have some yellows. The eye is edged in turquoise.
On each side of the caudal peduncle are two fixed spines or "scalpels" used for defense or dominance. Having one or two fixed blades are what places the Naso genus in the subfamily Nasinae. Caution needs to be exercised when handling surgeonfish as a cut from its scalpel can cause discoloration and swelling of the skin with a high risk of infection. The pain lasts for hours then still ends up having a dull ache. These fish are best captured using a double bag under water, rather than a net.
NOTE: At first we wondered if the photo above really is an Elongate Unicornfish, due to the similarity of this fish to the juvenile form of the Vlamingi Tang N. vlamingii. However there are definite distinctions and it does match the description that we found in Fishes of the Great Barrier Reef and Coral Sea, Revised edition, by John E. Randall, Gerald R. Allen and Roger C. Steene. There is also a very similar photo representation in Dr. Burgess's Atlas of Marine Aquarium Fishes, by Dr. Warren E. Burgess, Dr. Herbert R. Axelrod, and Raymond E Hunziker III.
Maintenance difficulty: Once eating, Elongate Unicornfish are hardy and easy to maintain as long as sufficient space is provided. Obtain a specimen that is at least 4" long as smaller ones rarely adapt to living in captivity. As they attain around 80% of their growth in the first 5 years of life, this means they are growing at a rate of approximately 3 - 4" per year. They must be housed in a large tank. It is best not to purchase small with the idea of "getting a bigger tank" later, as these fish will quickly outgrow a smaller tank. Four feet long is the minimum length for a small specimen, but as this would be quite temporary a six foot or larger aquarium would be better. Too small of an environment can stunt their growth and they can develop 'behavior problems'. A healthy Elongate Unicornfish will be swimming the length of the tank during the day. If you see any sulking, hiding behavior, this is an indication of stress. If their reason for sulking is not resolved or they are stressed for too long they may not recover.
They can handle a wide range of water parameters but will do best in an environment that provides consistency, not only in water conditions and quality, but also in decor and fellow inhabitants. They can be housed in a fish only tank, and as they will not harm corals or invertebrates they are compatible in a reef environment . However as it is also a large energetic fish, it may topple corals while swimming about in fast clips.
Naso tangs are continuous feeders and they need to be provided a proper diet. They are susceptible to nutritional disorders which may cause color loss and LLD (lateral line disease). Supplementing their diet with the addition of vitamin C to their food or adding a vitamin supplement directly to their water can help to avoid or aid in reducing these ailments. They are also susceptible to bacteria resulting from organic buildup which deteriorates water quality. Consequently they will need vigorous filtration, protein skimming, and regular small water changes.
Many of the Acanthuridae members are very colorful, active, and attractive to aquarists. But they do not produce as much skin mucus on their bodies as other fish and can be susceptible to diseases such as Marine Ich and Marine Velvet. Surgeonfish are definitely a candidate for quarantine when you first receive them. They can be treated successfully with medical care or copper drugs, but because they have an important microfauna in their digestive system, prolonged or continuous use of a copper treatment is not advisable.
In the wild a cleaner wrasse (Labroides sp.) will help them by taking parasites from their bodies, however these wrasses are extremely difficult to sustain in captivity. Alternative fish such as Neon Gobies (Gobiosoma sp.) or cleaner shrimp can help them by providing this cleaning service in the home aquarium.
Foods: The Elongate Unicornfish are primarily herbivores. Provide lots of algae, large chunk types of prepared frozen formulas containing algae or spirulina, freeze dried plankton, and flakes. Japanese Nori or other seaweed can be adhered to the aquarium glass with a vegetable clip. It will also feed on some frozen brine and mysis. An occasional live rock with micro and macro organisms will be greatly appreciated. Culturing macro algae like chaetomorphia in the tank is also a great idea. Feed at least 2 - 3 times a day in smaller amounts instead of a large quantity once a day. This will keep the water quality higher over a longer time.
Providing a vitamin supplement (including vitamin C) can help provide for their nutritional needs, and vitamin C can help prevent or reduce Lateral Line Erosion (LLE). This can be done by soaking dried pellets with liquid vitamins, adding vitamins to the food, or adding a liquid vitamin into the water. It is also said that pellets soaked in garlic may help fend off Marine Ich. Some hobbyists also report success with supplemental foods such as previously boiled or frozen zucchini, broccoli, spinach, and leaf lettuce.
Maintenance: A quick and agile swimmer it will spend a good deal of its time in the open water and moving in and out of areas providing some cover. They may jump out of an open aquarium, so be sure to have a lid. Frequent water changes are not necessary, rather normal water changes at 10% biweekly or 20% monthly are fine.
For more information see, Marine Aquarium Basics: Maintenance
There are some Acanthuridae members that are delicate and will require more specific care, but most will respond well if you employ a few technical considerations. All surgeonfish need an aquarium with plenty of aeration, a strong current will help to provide good oxygenation. Provide a large tank with plenty of space for swimming, especially for adult specimens, along with lots of rocks/ corals with crevices for retreating and for sleeping. This decor will lend itself to algae growth which these fish will enjoy grazing on.
Minimum Tank Length/Size:
A minimum 75 gallon (284 liters) temporarily for a juvenile, 180 gallon (680 liters) or more for an adult. Four feet long is the minimum length for a small specimen, but as this would be quite temporary a six foot or larger aquarium would be better. Too small of an environment can stunt their growth and they can develop 'behavior problems'.
Light: Recommended light levels
It nature it is found in sunlit areas. It can be kept under normal lighting conditions in the aquarium, but can also be kept under very bright light as long as some dimly lit spaces are provided.
This species lives in tropical areas. Temperatures between 75 - 82° F (24 - 28° C) will serve them well.
Water Movement: Weak, Moderate, Strong
Strong brisk water movement. All surgeonfish and tangs thrive with good water movement, need lots of oxygen, and love to have the water rushing over their gills. Provide turbid water conditions for this species.
Water Region: Top, Middle, Bottom
It will spend time in the open water and darting in and out of the rocks/ corals. It will sleep in crevices at night.
Social Behaviors: The great thing about all the species in the Naso genus is they are quite peaceful and unobtrusive making them an excellent addition to a community aquarium. The Elongate Unicornfish get along with most other marine fish and can be kept with a variety of tank mates including other genus' of surgeonfish. However unless you have a huge (hundreds of gallons) system, it is best to house just one Naso tang to a tank. Being an herbivore it is a good algae eater, but is also a large energetic fish and may topple corals while swimming about in fast clips.
Surgeonfish and tangs can be territorial, sometimes just with their own kind and sometimes with other species. Introducing a new surgeonfish into an aquarium that already houses one or more is usually a problem. It is best to initially introduce several species together rather than adding a new one later on. Though a large aquarium can help alleviate many problems, be aware of the social behaviors of any species you are considering to prevent compatibility problems.
At times you may put surgeonfish and tangs together with different genus' as long as there are no similarities. For example a large tank can house a Unicornfish, a sailfin tang, and a Hippo Tang without incident. Adding them together initially works best. When adding a new member to an established group, changing the rock work will often alleviate any aggression to the "new guy". A little chasing will occur, but usually nothing detrimental.
Sex: Sexual differences: No sexual difference is noted for this species. In general males of the Naso species will be larger and the caudal peduncle will be larger and more pronounced than on the females. On some species the tail is also longer.
Breeding/Reproduction: Some species of surgeonfish have spawned in public aquariums and there have been a few scattered reports of spawning in home aquariums, but regular spawning and the rearing of the young has not yet been reported.
Though the Elongate Unicornfish has not yet been bred in captivity, the Unicornfish spawn in pairs in the open water. The males can change part of their body into a brilliant color to court a female. A pair will rise to the surface to release their gametes. The eggs are pelagic with an extended larval phase, which probably accounts for the vast distribution of the Unicornfish.
For more information on breeding and the development of the fry, see: Marine Fish Breeding: Tangs.
Availability: Though still quite rare, the Elongate Unicornfish or Lopez's Unicornfish is becoming a bit more common in at retailers. They are occasionally available on the internet and are priced at about $70.00 USD and up.