The regal blue tang, also known as the hippo tang or palette surgeonfish, is famous for its vivid blue body, black palette marking, and yellow tail. Despite its celebrity status, this species grows large and requires a spacious aquarium. Blue tangs are prone to marine ich and must be quarantined thoroughly before introduction to a display tank.
Quick facts
| Scientific name | Paracanthurus hepatus |
| Max size | 12 in (30 cm) |
| Min tank size | 125 gal (475 L) |
| Temperament | Peaceful |
| Diet | Omnivore (herbivore-leaning) |
| Reef safe | Yes |
| Care level | Moderate |
| Origin | Indo-Pacific |
Overview
The following sections detail exactly how to keep this species thriving in a saltwater reef environment.
Tank requirements
A 125-gallon tank is the minimum for an adult specimen. Juveniles may start in smaller tanks but grow rapidly. Provide an open swimming lane along with rockwork for sleeping and hiding. Blue tangs often wedge themselves sideways into rock crevices at night—this is normal, not a sign of distress. Strong flow and excellent oxygenation are important.
Water parameters
Maintain standard reef aquarium parameters for long-term health:
- Temperature: 75–80 °F (24–27 °C)
- pH: 8.0–8.4
- Salinity: 1.024–1.026 sg
- Alkalinity: 8–11 dKH
- Ammonia / Nitrite: 0 ppm
- Nitrate: < 20 ppm (lower is better for a reef)
Stability is more important than hitting a specific number. Avoid sudden swings in any parameter.
Diet and feeding
Feed nori seaweed daily, spirulina pellets, frozen Mysis shrimp, and marine algae sheets. While classified as omnivorous, a large portion of their diet should be plant-based. Feed 2–3 times daily. A varied diet helps maintain their bright blue coloration and supports immune health.
Behavior and compatibility
Surprisingly peaceful for a tang. They coexist well with most reef fish, including clownfish, wrasses, and gobies. They can be kept with other tang species in sufficiently large tanks. Avoid keeping with overly aggressive species that may stress them, as stressed blue tangs are highly susceptible to ich.
Breeding
Pelagic spawners. Captive breeding has been achieved but remains extremely difficult and is not commercially viable yet. Nearly all specimens in the hobby are wild-caught.
Tips for success
- Quarantine for 72+ days using copper or tank transfer method—blue tangs are ich magnets.
- Provide daily algae (nori on a clip) for digestive and immune health.
- Expect this fish to grow large—plan for a 125+ gallon long-term home.
- Wedging sideways into rocks at night is normal sleeping behavior, not a sign of illness.
- Maintain excellent water quality—blue tangs are sensitive to elevated nitrate.
Frequently asked questions
Why does my blue tang always get ich?
Blue tangs have a thin slime coat that makes them more susceptible to Cryptocaryon irritans than other fish. Proper quarantine, low stress, good nutrition, and stable water parameters are essential for keeping them ich-free.
Can I keep a blue tang in a 55-gallon tank?
Not long-term. While juveniles may survive temporarily in a 55-gallon, adult blue tangs reach 10–12 inches and need 125+ gallons to swim comfortably and stay healthy.
Is the blue tang really called Dory?
The character Dory from the popular animated films is modeled after the regal blue tang (Paracanthurus hepatus). The films unfortunately led to a surge in demand for wild-caught specimens, stressing wild populations.
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