Blue Hippo Tang - Paracanthurus hepatus

SM (2-2.5")

$99.99

Blue Hippo Tang - Paracanthurus hepatus

Reef Safe Tang

$99.99

SKU: TANGxBlueSM

Size Tiny (<1.25") Small (1.25-2") SM (2-2.5") Medium (2.5-3.5") ML (3.5-4.25") Large (4.25-5.25")

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Diet

algae/nori spirulina mysis brine shrimp

Min Tank Size 125 gallons

Temperament Semi-aggressive

Reef Safe Yes

Overview Quick summary and key facts about this species.

Overview:

The Blue Hippo Tang (Paracanthurus hepatus), also called the regal tang, is a highly active marine fish that needs a large, stable saltwater aquarium. Despite its popularity, it is not a beginner fish. Adults require at least 180 gallons, with plenty of open swimming space, strong filtration, and vigorous water movement. A mature tank with stable salinity, temperature, and low nitrate is essential. Ideal conditions are 72–78°F, specific gravity 1.020–1.026, and pH around 8.1–8.4. This species is sensitive to poor water quality and sudden changes, so consistent maintenance is critical. Provide rockwork for security, but leave ample room for cruising. Good oxygenation and a secure lid are also important, as active tangs can jump when startled.

Diet and Feeding:

Blue Hippo Tangs are primarily herbivores and should be fed a varied diet focused on marine algae and seaweed. Offer nori or other dried sea vegetables several times per week, ideally daily, using a clip or feeding station. Supplement with high-quality herbivore pellets, spirulina-based flakes, and frozen foods such as mysis or enriched brine shrimp in moderation. Frequent small feedings are better than one large meal. A tang that is underfed may become stressed, aggressive, or more prone to disease. Including algae-based foods supports digestion and helps maintain strong coloration and overall condition. Avoid overfeeding protein-heavy foods, which can lead to digestive issues and unnecessary waste in the aquarium.

Compatibility:

Blue Hippo Tangs are generally peaceful toward many community reef inhabitants, but they can become territorial with other tangs or similarly shaped fish. They do best with non-aggressive tankmates that will not compete excessively for food or space. Avoid housing them with very aggressive species that may intimidate them, especially in smaller tanks. If keeping multiple tangs, introduce them carefully and provide a much larger aquarium with varied swimming routes and hiding places. They are usually reef-safe and compatible with most corals and invertebrates, though their size and activity can disturb delicate decorations if the tank is crowded. They may show nipping or chasing behavior if cramped, stressed, or competing for algae.

Health and Quarantine:

Blue Hippo Tangs are especially prone to marine ich, velvet, and other stress-related parasitic infections, so quarantine is strongly recommended before introduction to the display tank. A separate quarantine tank allows observation, prophylactic treatment if needed, and a better chance of preventing disease spread. Watch for rapid breathing, flashing, loss of appetite, spots, or pale coloration. Because tangs are highly sensitive to environmental instability, excellent water quality is one of the best preventive tools. Maintain low ammonia and nitrite, perform regular water changes, and minimize handling. Stress reduction is crucial: provide stable conditions, proper diet, and adequate swimming room. Healthy Blue Hippo Tangs are active, alert, and constantly grazing; any lethargy or reduced feeding should be addressed promptly.

Care & Diet Feeding, nutrition, and best practices.

Diet Type: Omnivore

Diet and Feeding: Blue Hippo Tangs are primarily herbivorous, grazing on marine algae, film algae, and detritus in the wild, and it is beneficial to replicate this with a diet built around nori, dried seaweed, spirulina-based flakes, and high-quality herbivore pellets as the main staples. To ensure balanced nutrition, supplement regularly with small portions of mysis shrimp, brine shrimp, chopped seafood, and algae-enriched frozen foods as occasional treats. Offer seaweed on a clip or feeding station and rotate staple foods to encourage natural foraging behavior and steady grazing throughout the day. Feed small amounts multiple times daily, and be careful to prevent overfeeding, as this helps maintain water quality and supports long-term health.

algae/nori spirulina mysis brine shrimp

Behavior Temperament, activity level, and interactions.

Temperament: Semi-aggressive

Blue Hippo Tangs are highly active, open-water cruisers that need ample uninterrupted swimming space along with plenty of rockwork and caves for shelter and nighttime security. They are generally peaceful toward most tank mates but can be assertive with conspecifics and other tangs, especially in confined quarters, so careful stocking and introduction order matter. A minimum tank size of 180 gallons is recommended, with a long layout that provides visual barriers, swim lanes, and structured rockwork to reduce stress and territorial tension. In reef aquariums they are typically reef-safe and coexist well with other non-aggressive community species, though they may become stressed around overly boisterous or similarly shaped fish. Their diet is primarily herbivorous, focused on filamentous algae and marine plant matter, and they benefit from regular feedings of algae-based preparations such as nori, spirulina, and herbivore pellets. Occasional meaty foods may be accepted, but their long-term health depends on consistent grazing opportunities and a varied, vegetable-rich regimen.

Tank & Aquascape Tank requirements and aquascaping tips.

Min Tank Size: 125 gallons
Max Size: 10 inches
Care Level: Moderate
Origin: Indo-Pacific

Compatibility Tank mates, aggression, and introduction order.

Temperament: Semi-aggressive
Reef Safe: Yes

Reef & Health Reef safety, common issues, and prevention.

Reef Safe: Yes
Care Level: Moderate

FAQs Answers to the most common questions.

Why does my Blue Hippo Tang (Paracanthurus hepatus) keep getting ich or velvet even in a “clean” reef tank?

Blue Hippo Tangs are one of the most parasite-prone tangs in the hobby because they stress easily during capture, shipping, and acclimation, and that stress can trigger marine ich or velvet. Even when water quality looks perfect, this species often arrives with a compromised mucus coat and a suppressed immune system. The best prevention is quarantine before the fish ever enters the display, with close observation for at least 30 days and proactive treatment if needed. A healthy Blue Hippo Tang should be eating aggressively and swimming normally; if it starts flashing, breathing fast, or hiding, act quickly because velvet can move very fast on this species.

How big of a tank does a Blue Hippo Tang really need, since many stores sell juveniles?

Juvenile Blue Hippo Tangs are often sold very small, but they grow into active, open-water swimmers that need a much larger system than their juvenile size suggests. A long tank is far more important than a tall tank because they are constant cruisers. For long-term care, a minimum of 6 feet of swimming length is strongly preferred, with larger being better as the fish matures. In undersized tanks, they commonly become stressed, pace the glass, or develop head-and-lateral-line erosion from chronic confinement and poor environmental quality.

Why does my Blue Hippo Tang go from electric blue to a dark, almost gray color?

Blue Hippo Tangs can dramatically darken when stressed, sleeping, or feeling threatened. This color change is often a normal stress response, especially after lights out, during transport, or when a dominant tankmate is harassing them. If the darkening is paired with clamped fins, rapid breathing, or refusal to eat, it usually means the fish is not settled. A healthy specimen will usually return to its vivid blue with yellow tail and dark markings once it feels secure, is feeding consistently, and has enough swimming space and hiding spots.

What foods do Blue Hippo Tangs need to keep them healthy and prevent head and lateral line erosion?

Blue Hippo Tangs are primarily herbivores/omnivores that do best on frequent, varied feedings with a strong algae component. The core diet should include marine algae sheets, quality algae-based pellets, and frozen foods with greens mixed in. They also appreciate small amounts of meaty foods like mysis, but plant matter should remain the foundation. To help reduce the risk of head and lateral line erosion, keep the diet rich in vitamins and avoid relying on only one food type. Also, strong water quality, low stress, and stable minerals are just as important as diet for preventing HLLE in this species.

Can a Blue Hippo Tang live peacefully with other tangs, especially in a reef tank?

Blue Hippo Tangs can coexist with other tangs, but only when the tank is large enough and the introduction order is managed carefully. They are generally not the most aggressive tang, but they can become territorial if crowded or introduced into an established tang hierarchy. In smaller tanks, they may get bullied by more dominant species like Sohal, Powder Blue, or Achilles tangs. In a reef tank, they are usually safe with corals, but the key is giving them enough space, multiple feeding stations, and enough rockwork to break sight lines so they don’t feel trapped or forced into constant conflict.

Goes well with:

You will receive a fish SIMILAR in design and size to the fish in the photo. This is NOT a WYSIWYG fish.

The Blue Hippo Tang (Paracanthurus hepatus), also called the Regal Tang or “Dory” fish, is a standout reef-safe surgeonfish prized for its electric blue body, bold black patterning, and constant, active swimming. Like most tangs, it’s a dedicated grazer that helps manage nuisance algae when given ample space, high water quality, and a steady supply of marine-based greens.

Scientific Name: Paracanthurus hepatus
Max Size: Up to 12 inches
Diet: Primarily herbivore (marine algae/seaweed) with meaty foods offered occasionally
Tank Size: 125+ gallons (180+ recommended for adults)
Temperament: Semi-aggressive (generally peaceful; may be territorial with other tangs)

Best kept in a mature, well-oxygenated aquarium with strong filtration, brisk water movement, and open swimming lanes. Provide rockwork and caves for shelter—Blue Hippo Tangs often wedge themselves into crevices to rest, especially when newly introduced.

Reef Safe: Yes (does not nip corals or invertebrates)
Activity Level: High—needs long stretches of open water to cruise
Compatibility: Usually peaceful with most community reef fish; use caution mixing with other tangs, especially similar-shaped species
Care Level: Moderate—space, diet, and stability are key

Diet & Feeding Tips

To support long-term health and coloration, feed a varied menu focused on marine plant matter. Offer seaweed daily and rotate quality prepared foods to reduce nutritional gaps.

Nori/seaweed sheets (daily)
Spirulina-based flakes or pellets
Frozen herbivore blends
Occasional meaty options (e.g., mysis) for variety—not as the main diet

Habitat & Water Conditions

Blue Hippo Tangs are sensitive to rapid changes and do best with stable reef parameters and consistent maintenance. Quarantine is strongly recommended, as tangs are commonly susceptible to external parasites in stressful transitions.

Temperature: 74–80°F
pH: 8.1–8.4
Alkalinity: 8–12 dKH
Specific Gravity: 1.020–1.025
Setup: Strong flow, high oxygenation, ample swimming room, and multiple hiding spots

Temperament & Stocking Notes

In a properly sized tank, the Blue Hippo Tang is a great centerpiece fish for reef communities. Introduce with care if adding other tangs—larger aquariums, plenty of rockwork, and adding tangs in a planned order can help reduce territorial behavior.

Good tankmates: Clownfish, wrasses, gobies, many angelfish (species-dependent), other peaceful reef fish
Avoid/Use caution: Small tanks, overcrowded systems, and mixing with similarly sized tangs in limited space

FAQ

Will a Blue Hippo Tang eat algae? Yes—this species grazes on algae and benefits from daily seaweed feedings, though it won’t replace good nutrient control and maintenance.
Can I keep a Blue Hippo Tang in a 75-gallon tank? It may be temporarily housed when small, but long-term success is best in 125+ gallons (larger is better) due to its adult size and constant swimming.
Is the Blue Hippo Tang reef safe with corals? Generally yes—it’s considered reef safe and typically ignores corals and most invertebrates when well-fed.