A Unicorn Without A Horn

The Humpnose Unicorn Tang is a gorgeous fish that also gets called the Humphead Tang and Humpnose Unicornfish. Their Scientific name is Naso tuberosus, Naso for nose; many of the fish in this genus have noses that are unique, and this one's nose is well, tuberous. The other fish in the genus that is also commonly called a Unicorn is the slightly more famous, and closely related reef fish, Naso unicornis, which in adulthood grow a distinctive single horn out of their forehead. The humpnose Unicorn shares many traits with the true Unicorn, but instead of the fairy tale inspired horn, these big, beautiful fish grow out a bump in its place that seems more like an Elephant Seal or a Humphead Wrasse.

The Humpnose Unicorn Tang is a common fish throughout the Indian Ocean and the Western Pacific Ocean, where it is almost always harvested as a food fish; they are much less frequently seen in home aquariums. Found near the coral reefs of tropical seas, as juveniles they are pale gray with tan / orange-ish spots that turn darker as they age, and remain on the adult fish as dark blue, dark gray or black dots. These juveniles are often found in large schools with other species of juvenile Surgeonfish, but adults are usually solitary. Individuals have been identified at stupefying depths, but they are almost always found in less than 100 feet of water.

Like all its relative Naso Tangs, Humphead Unicorn Tangs can get pretty big. The largest one on record came from the waters around Taiwan and was just shy of two feet long. They reach adulthood at around eight inches, and most won't ever get larger than 15 or 16 inches, in the wild or captivity. Regardless, fish of this species will commonly get up to a foot plus and as such, are going to need a very big aquarium. They are also an incredibly active fish, with big appetites and we suggest having a bare minimum of 240 gallons for one, and larger would be better. They will appreciate as much flow as is humanly possible. Rockwork should allow them plenty of space to hide and graze, while leaving open space for them to swim. They don't need any substrate and are great candidates for bare bottom aquariums as this will help prevent waste from building up in the display.

A variety of foods should be offered to any surgeonfish, and these are no exception. We feed them lots of algae like Nutramar OGO and Nori as it is important for how their digestive systems work. However, a surprisingly large component of their diet is small invertebrates that are both intentionally eaten and accidentally ingested with their algal diet. To this end, we also give them a nutrient dense pellet, which is a must for their nutritional needs. In house we utilize Nutramar's Algae and Color Balance pellets and shots. The shots are great because they offer a way for the fish to graze on the food, which is a natural feeding behavior for them. For fish who don't take to pellets immediately, they can be mixed with some thawed, meaty food like Gamma Mysis or any of their enhanced Brine Shrimp products to fool the fish into taking the pellets. They will very quickly graze any hair algae and even some caluperas out of existence in a tank.

With a diet like this, they produce quite a bit of waste, I mean, some really serious poos. This in turn produces quite a bit of food for other organisms in your aquarium, but it can also adversely affect water quality if your filtration and water change schedule are not up to the task. They need clean water, and nitrates should be kept under 5ppm, with a correspondingly low phosphate (0.02-0.10). Temperature can be anywhere from 70 to 78 and pH should be stable but could be anywhere from 8.0 to 8.4. Specific gravity can be anywhere from 1.021 to 1.026 (and should also remain nice and stable).

All the Naso tangs are peaceful fish, but they usually aren't very shy. They are well defended with their tail spines and are fast swimmers. To this end, they can be kept with all but the most aggressive fish and will not intentionally bother pretty much anything. When choosing smaller fish to house with them, keep in mind that the Humpheads are big and busy and active, and the more timid fish may be constantly scared into hiding because of this. We have kept Humphead Unicorns in displays with many other genus of surgeon fish, but they should probably be the only Naso genus tang in your tank unless you have an absolutely massive display. They are among the most reef safe fish out there; they are incredibly unlikely to bother your corals or any other invertebrates you keep them with.

Naso tuberosus are very hardy and “personable” fish in captivity, growing to know their aquarists and generally accepting prepared foods without much fuss. Frequently, you will see Naso genus tangs listed as “venomous.” This is because they have spines at the base of their tail fin (remember, this is a Surgeonfish) and those have a mild venom associated with them. These are like small blades and can leave you with a cut that hurts more than it should. Careful handling can eliminate this risk. They should never be handled with fine nets because these same spines can get caught in the webbing injuring the fish. A quick google will show you that some people caution against keeping any Naso in acrylic aquariums because of the scratch risk associated with the scalpels, but this has not been a concern in the displays we've seen.

If you have a display that is big enough, these make an excellent showpiece fish for aquariums with or without corals. These personable fish take quickly to captive diets and conditions and make totally reef safe additions to any aquarium that they can fit in. If you're interested in Naso tuberosus, head to your LFS and ask them about getting you a Humphead Unicorn Tang from Quality Marine today!