Purple tang
Zebrasoma xanthurum
Also known as: Dusky sailfin tang, Red Sea sailfin, Yellow tang, Yellowtail sailfin tang, Yellowtail surgeonfish, Yellowtail tang
This is the deep-purple tang with the bright yellow tail - it cruises the rockwork all day picking at algae like a little lawnmower. It has that classic Zebrasoma "sailfin" shape and a real attitude if you crowd it with other tangs, so give it room and let it be the boss (or at least think it is).
The Purple tang has a vibrant purple body, yellow accents on the tail, and a distinctive spiny dorsal fin.
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Quick Facts
Size
36.7 cm
Temperament
Semi-aggressive
Difficulty
Intermediate
Min Tank Size
125 gallons
Lifespan
5-10 years
Origin
Western Indian Ocean (Red Sea to Persian Gulf, recorded from Maldives)
Diet
Herbivore - lots of marine algae/nori and spirulina-based foods, plus occasional meaty frozen foods for variety
Care Notes
- Give a purple tang real swimming room - I would not do less than a 4-6 ft tank (125+ gallons), with lots of rock caves plus open lanes to cruise.
- Keep salinity steady around 1.025-1.026 and temp around 77-79F; they get crabby and spot-prone when swings happen.
- Feed like a grazer: nori on a clip daily (swap sheets before it turns to mush), plus a mix of spirulina pellets and frozen mysis/brine a few times a week.
- They can be a bully to other tangs, especially other Zebrasoma (yellow/scopas/sailfin) - if you want multiple tangs, add the purple last and use an acclimation box.
- Reef-safe with corals, but they will mow down some macroalgae and can pick at new soft algae films all day, so plan your refugium expectations accordingly.
- Watch for ich and velvet - purples are magnets for it; quarantine if you can, and run a UV if your system tends to get outbreaks.
- Head and lateral line erosion (HLLE) can show up if diet is weak or stray voltage is a thing - keep the algae-heavy diet going and check for electrical leaks if you see pitting.
- Breeding at home is basically not happening; they are open-water spawners, so focus on keeping one fat, active, and not stressed instead.
Compatibility
Good Tankmates
- Clownfish (Ocellaris or Percula) - they stick to their corner and usually get ignored. Add the tang later so it does not try to 'own' the whole rockwork right away.
- Fairy and flasher wrasses (Cirrhilabrus and Paracheilinus) - fast, confident swimmers that can handle a little attitude without escalating into a brawl.
- Reef-safe dwarf angels like a Coral Beauty or Flame Angel - similar vibe, busy all day, and they normally sort out pecking order quickly in a decent sized tank.
- Rabbitfish (Foxface) - great algae buddy and usually too chill and too 'spiky' for the tang to bully much. Give them swimming room and lots of grazing.
- Halichoeres wrasses (like Melanurus) - active and not easily pushed around. They also do their own thing hunting pods and pests.
- Most reef gobies and blennies (watchman goby, tailspot blenny) - bottom perchers that stay out of the tang's lane. Just make sure they have holes and ledges to claim.
Avoid
- Other tangs in the same 'body shape' club - especially other Zebrasoma like Yellow tang, Sailfin, or another Purple tang. This is where you see the real attitude come out, and it can turn into nonstop tail slapping and chasing.
- Acanthurus tangs like Powder Blue, Achilles, or Sohal - you are basically asking for a turf war unless the tank is huge and you really know what you are doing.
- Very timid, slow fish (Firefish, small cardinals that hide all day) - a Purple tang can harass them just by being a pushy, high-energy roommate.
Where they come from
Purple tangs (Zebrasoma xanthurum) are Red Sea fish. That is a big reason they have that deep, saturated purple that holds up under reef lighting. They are built for grazing all day on rocky reefs with lots of surge, so they do best in tanks that give them room and a steady supply of veggie food.
Setting up their tank
Give a purple tang space first, rockwork second. They are a constant swimmer, and they like doing laps with quick turns into caves. I would not keep one in anything under 4 feet long, and 5-6 feet is noticeably better once it puts on size and confidence.
- Tank size: 120 gallons minimum is a comfortable starting point, bigger if you want multiple tangs
- Aquascape: build a long rock ridge with caves and swim-throughs, but keep open water across the front
- Flow and oxygen: moderate to strong flow and good surface agitation (they are active and like clean, oxygen-rich water)
- Typical reef parameters: 1.025-1.026 salinity, 76-79F, stable alkalinity and pH, low ammonia/nitrite always
- Cover: they can startle and wedge themselves into rock, so make sure rock is stable and not teetering
If you are adding a purple tang to a tank with other tangs, an acclimation box for a few days can save you a lot of chasing and fin damage.
They appreciate a little bit of "ugly" in the tank - some natural film algae and grazeable spots. A spotless, brand-new tank with zero algae often leads to a fish that looks fine but slowly loses weight because it is missing that all-day picking.
What to feed them
Think of them as a vegetarian that still wants some meaty snacks. Mine did best on frequent small feedings, with nori available most days. If you only feed a cube once a day, a purple tang will still beg... but it can slowly get pinched in the belly.
- Nori/seaweed sheets on a clip (rotate red/green/brown if you can)
- Quality herbivore pellets or flakes (look for spirulina and seaweed-based foods)
- Frozen foods for variety: mysis, brine, and reef blends (not the whole diet, just part of it)
- Occasional treats: chopped clam or shrimp, especially helpful for new/shy fish to start eating
Put the nori clip in different spots. If it always goes in the same place, the tang will claim that corner and start "guarding" it from tankmates.
How they behave and who they get along with
Purple tangs are bold and can be spicy. Mine was a model citizen with wrasses, clowns, gobies, and most reef fish, but it absolutely had opinions about other algae-eaters. Expect some showing off with the scalpel (the little razor at the base of the tail) and a lot of side-posturing.
- Generally fine with: clownfish, most wrasses, cardinals, anthias, blennies (watch turf-war blennies), rabbitfish (sometimes), reef-safe angels with caution
- Can be rough with: other Zebrasoma tangs (yellow, scopas, sailfin), similar-shaped tangs, new additions that want the same grazing lanes
- Safer tang combos: different body shapes (for example a purple tang with a bristletooth tang like a kole) in a large tank with lots of rock and multiple feeding stations
That tail scalpel is not a joke. Netting can turn into a mess fast. I use a large specimen container or bag-in-container method instead of a net whenever possible.
Order of addition matters. If the purple tang goes in first, it often tries to "own" the whole tank. Adding it later, or at the same time as other tangs, usually goes smoother.
Breeding tips
In home aquariums, breeding purple tangs is basically a lottery win. They are open-water spawners with tiny pelagic larvae that are extremely difficult to raise without specialized setups (and a lot of live plankton production).
What you might see, though, is dusk behavior: increased swimming, circling, and color shifts. It is fun to watch, but I would not build a plan around raising babies unless you are already deep into marine larval rearing.
Common problems to watch for
The big three with purple tangs are ich, HLLE, and weight loss. They are tough once settled, but they do not love big swings or being bullied off food.
- Marine ich/white spot: tangs are magnets for it, especially after shipping or aggression stress
- HLLE (head and lateral line erosion): often tied to stress, diet issues, and long-term water quality problems
- Weight loss and "pinched" belly: usually from not enough algae-based food or too few feedings
- Fin tears and tail wounds: from tang disputes or getting wedged in rock
- Coral nipping: uncommon, but a hungry tang may sample fleshy LPS or pick at polyps while grazing
Have a plan for disease before you buy the fish. A simple quarantine setup and a way to treat parasites is a lot easier than trying to catch a purple tang out of a rock-filled reef after spots show up.
If you see pale patches or scrapes, check for bullying and check where it sleeps. Purple tangs wedge into rock to sleep and can scuff themselves if the fish panics at night or the rock has sharp edges.
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