Blue Hippo Tang (Paracanthurus hepatus) saltwater aquarium fish

Paracanthurus hepatus is instantly recognizable: a laterally compressed, oval-bodied surgeonfish carrying a brilliant blue field interrupted by a bold black palette-shaped marking, finished with a yellow caudal fin and yellow pectorals. The species ranges through the tropical Indo-Pacific, where it favors clear outer-reef zones and channels swept by substantial current. Adults commonly reach about 12 inches. Like other surgeonfishes, it carries a sharp folding spine on each side of the caudal peduncle, a defensive structure worth respecting during netting and transfer.

Adult housing should begin at 180 gallons, and a tank at least six feet long gives this open-water swimmer the horizontal runway it uses constantly. Some aquarium references cite a lower figure near 125 gallons, but the larger footprint better reflects adult size and activity. Arrange live rock or comparable structure so that the fish has secure retreats, since an alarmed specimen bolts into reef architecture rather than fleeing into open water.

A mature, stable system suits this fish best. Pristine, well-oxygenated water supported by powerful filtration, protein skimming, and a consistent water change schedule keeps a specimen of this size in good condition. Because it naturally occupies current-swept reef terrain, generous water movement through the display is appropriate and encourages more natural swimming behavior.

On the reef, this tang feeds primarily on zooplankton, taking algae only occasionally, which makes it a genuine omnivore rather than a dedicated grazer. Captive feeding should reflect both halves of that diet. Offer plankton-like and meaty marine preparations regularly while maintaining steady access to macroalgae, prepared marine-algae foods, seaweed, or nori.

Feed small portions across the day rather than a single large meal, and keep dried marine algae available at least three times per week, clipped where the fish can graze without competition. A varied rotation supports color and condition in a fish that spends most of its day swimming. Watch that faster or more assertive feeders do not intercept its share at feeding time.

Mysis Shrimp Marine Algae Nori Sheets Frozen Plankton Macroalgae Chopped Meaty Seafood Prepared Herbivore Pellets
In the wild this species forms loose aggregations above the reef, with juveniles and subadults clustering near branching corals and wedging tightly into the branches when threatened. Aquarium specimens are active, largely open-water swimmers that cruise the display throughout the day and use rockwork as refuge. Toward unrelated community fish it is generally agreeable, but it can turn territorial toward its own kind and toward other tangs, so the semi-aggressive label is earned within its own family.

Multiple specimens should only be attempted in a sufficiently large system with abundant cover, and all individuals should be introduced at the same time to blunt territorial disputes. Avoid pairing it with bullying species or aggressive feeders that would keep it from eating. It is considered reef safe, with no documented pattern of consuming corals or preying on shrimp, crabs, snails, clams, or small fishes.

FAQ

Frequently Asked Questions

About the Blue Hippo Tang

  • How large an aquarium does a Blue Hippo Tang require?
    Plan on a minimum of 180 gallons for an adult, with a tank at least six feet long. Both swimming room and secure rockwork cover are essential.
  • Is the Blue Hippo Tang strictly an algae eater?
    No. It feeds mainly on zooplankton in the wild with occasional algae, so captive menus should combine plankton-like or meaty marine foods with consistent marine algae or seaweed.
  • Can it be kept with other tangs or additional Blue Hippo Tangs?
    It is usually agreeable toward unrelated fish but can become aggressive toward its own species and other tangs. Attempt multiples only in a large system with plenty of cover, introducing all individuals at once.