Surgeonfish are all beautiful but the midnight black and orange Achilles tang is one of the most desirable members of this family. Many tangs are also known to be picky eaters and a challenge to care for. But how much of this is true for the Achilles tang?
What is the Achilles Tang?
The Achilles tang is a member of the family Acanthuridae, which includes tangs, surgeonfish, and unicornfish. Most of them are marine herbivores and omnivores who need more variety in their diet than other saltwater fish.
Surgeonfish get their name from the retractable, razor sharp spine along their tails. The spine is a modified spine that’s as sharp as a surgeon’s scalpel. Tangs and surgeonfish use this scale for defense, slapping it against predators that get too close.
They will also use it in fights with each other. Since these fish are territorial and aggressive towards one another, it’s easy for a dominant fish to kill any rivals it dislikes.
A surgeonfish’s spine is also dangerous to you if you aren’t careful. Keep your hands clear of a tang in a net. And when bringing them home, check on the bag every so often as the tail spine may pierce the plastic bag.
Achilles tangs have a wide distribution throughout the Pacific Ocean. They are found on reefs throughout Oceania, as well as Hawaii and other atolls in the middle. Their range also includes Baja California and other spots along the Pacific coast of Mexico.
- Common Names: Achilles Tang, Red Tail Surgeonfish, Achilles Surgeonfish, Redspot Surgeonfish
- Scientific Name: Acanthurus achilles
- Origin: Pacific Ocean
- Length: 10 inches
- Tank Size: 125+ gallons
- Temperament: Semi-Aggressive
- Ease of Care: Difficult
Achilles Tang Care
Achilles marine tangs are active, disease-prone, and pollution-sensitive fish that even expert saltwater aquarists have trouble with. Unless you have a large tank, years of experience, and constant access to several kinds of marine macroalgae, I don’t recommend keeping the Achilles tang.
Achilles Tang Tank Size
The more spacious you make your Achilles tang tank size, the better. These fish are active swimmers that will utilize all of the room you provide them. As rock grazing fish, tangs need room to keep from overgrazing algae and biofilm.
That need for space is also part of the reason why they are so territorial. If another algae-eating fish comes to eat their food it could take weeks to regrow. Achilles tangs aren’t as large as some other surgeonfish species. But at 10 inches they need plenty of room.
For these reasons 125 gallons is the minimum for an Achiles tang. Larger is better if you have the space and time for maintenance. Contrary to the expectations of beginners, larger tanks are somewhat easier to manage than smaller ones.
A large aquarium dilutes pollutants that accumulate. In a small aquarium, even a tiny amount of ammonia will concentrate to dangerous levels. But larger tanks are more stable environments, which sensitive fish like Achilles tangs need most.
Water Conditions for an Achilles Tang
If you want to keep an Archilles tang then your water quality must be impeccable. Ammonia and nitrite levels need to stay at 0 parts per million. Even a small increase will lead to stress, loss of appetite, and eventual death.
Low levels of nitrate are acceptable if you have corals that need it for food. But don’t allow concentrations to rise beyond 10 ppm.
Detectable nitrogenous waste sometimes suppress their immune systems enough for marine ich to take hold. Tangs are prone to the disease and difficult to cure. A protein skimmer is a good addition to their tank, even if you don’t keep corals. Using a protein skimmer helps prevent dissolved proteins from decaying into ammonia.
Water temperatures of 72-80℉ are preferred by Achilles tang fish. The pH (8.0-8.4) and other chemistry parameters should fall along standard marine fish concentrations.
You don’t need to monitor strontium, magnesium, and other elements unless you keep reef building corals. All marine salt blends carry enough of these elements for Achilles tangs.
Water flow and good oxygenation are also critical to success. An aquarium powerhead with moderate flow will provide Achilles tang fish with current to work against. Make sure any corals and tank mates also prefer flow since not all do.
What Does an Achilles Tang Eat?
An important aspect of Achilles tang care is ensuring your fish get the right diet. These are herbivores that eat marine macroalgae. Algae are vitamin-rich and offer plenty of roughage and fat. Elements that low quality prepared foods often lack.
These tangs do consume small amounts of animal protein as well. Brine shrimp and mysis shrimp should be offered a few times per week. But pieces of macroalgae clipped in place are what they eat. Tangs will also eat terrestrial vegetables like zucchini and spinach.
Achilles tangs are prone to dietary deficiencies if fed prepared food alone. Hole in the head (HITH) disease is the most common manifestation. Also known as lateral line disease, HITH shows up as pits that form in the skin.
The holes are usually along the head and lateral line but may show up elsewhere. As the disease grows worse the pits will become permanent and grow infected with opportunistic bacteria.
Achilles Tang Tank Mates
Achilles tang fish complicate matters even more by being semi-aggressive. Tangs save the worst of their behavior for each other, however.
They are trying to save as much space for growing algae as they can. So even tangs that don’t look similar in color or shape may be bullied. But fish that aren’t similar in color may be the target of aggression from an Achilles tang.
Despite this temperament, you don’t want to keep an Achilles tang with other semi-aggressive fish. Saltwater angelfish are an exception but wrasses, triggerfish, and other fish of this temperament will cause the tang too much stress. And given how sensitive they are, it’s best if the tang is at the top of the aquarium hierarchy.
Fish that are peaceful but fast moving are also good tank mates. Anthias, chromis damselfish, and lyretail angelfish (Genicanthus sp.) all enjoy moderate water flow and spacious aquariums.
Breeding the Achilles Marine Tang
Spawning the Achilles tang hybrid is impossible to do in all but the largest of aquariums. For starters, these fish are very aggressive towards each other. They will slash rivals using their tail fins, which may kill or create wounds that get infected.
Once they are in the mood to spawn, Achilles tangs form groups. They are pelagic spawners, meaning they release their eggs and sperm as a cloud into the water. Where they mix and then float along as part of the marine zooplankton population.
The fry float with the zooplankton, feeding on these microscopic animals until they grow large enough. They then descend onto the reef, switching to algae and putting on size and color.
Since Achilles tang fry have a planktonic phase, captive breeding is impossible for now. They would be sucked into any filter or protein skimmer used in the aquarium.
Conclusion
Achilles tangs are specialty fish that should be kept only by advanced aquarists. It takes a solid foundation of marine fish care to have a chance at keeping one alive. And even if you do, the tang may still die since they are stressed by both capture and shipping.
FAQs
Achilles tangs are one of the more difficult marine aquarium fish to keep. They require lots of space and pristine water conditions. Nitrogenous waste amounts must be low and oxygen levels high. Achilles tangs also need a diet rich in macroalgae and other vegetation. Or else they will suffer from HITH disease and other vitamin deficiencies.
As rare, wild caught fish, expect to pay $300-$700 for an Achilles tang. Even small juveniles are expensive animals.
