Lightly Medicated | Blue Hippo Tang (Paracanthurus hepatus)

What “Lightly Medicated” means

This is the same animal as our non-quarantined listing, held briefly in our systems and given one short prophylactic course — a light treatment for ich and for internal and external worms — then observed eating in front of us before it goes home.

A light course knocks the parasite load down. It does not guarantee full removal, and we will not pretend otherwise. Ich is only killed in its free-swimming stage, and a short treatment window can miss cysts entirely; worm burdens can survive a single dose. Clearing an animal takes the full quarantine window — 40 to 90 days depending on the species — which is exactly what the Quarantined listing is for. This tier buys you a lower parasite load and a fish we have watched eat, not a cleared animal.

We condition the fish on our end. Every animal we medicate is brought back onto prepared food on our own systems and is eating before it leaves — in practice it is rare for a lightly medicated fish to ship out and arrive sick. Do the same at your end: get it eating in your aquarium before you count it settled.

When it ships

Plan on 5–7 days on our systems for the treatment course, and it does not leave until it is eating. If the animal is not already in our systems we source it first — allow up to two weeks for it to reach us before that clock starts. From the day you order, plan on roughly three weeks in total.

The guarantees

• Shipped orders: 24-hour live guarantee from confirmed delivery.
• In-store pickup: 7-day live guarantee — bring a water sample from your aquarium so we can test it before your livestock goes home with you.

Want the full program — treated, observed, confirmed eating, and covered for 28 days on pickup? That is the Quarantined listing. Run your own quarantine and just want the fish this week? The non-quarantined listing is cheaper still. The whole ladder is explained in Quarantined vs Non-Quarantined.

Paracanthurus hepatus is the fish that launched a thousand reef aquariums after Finding Nemo, but the real animal is considerably more interesting than the cartoon version. That electric-blue body with black “palette” markings and yellow tail hides a retractable scalpel blade at the caudal peduncle — a keratin-sheathed spine that surgeonfish deploy during territorial disputes — and startled individuals will jump from open-top tanks without warning. They do it fast enough that it looks like the fish teleported out of the water.

Juveniles wear the same electric blue with cleaner, sharper black markings; as the fish matures, the markings soften and the black pattern expands slightly. In the wild, juveniles aggregate in branching coral colonies (Pocillopora, Acropora) for shelter, retreating into the coral structure when threatened — behavior that’s completely impractical to replicate in captivity but explains why they’re naturally skittish in open environments without adequate rockwork refuge.

They’re herbivores that need nori and algae-based foods as the foundation of their diet, not just fish food they happen to accept. A Blue Hippo Tang fed primarily on meaty foods develops HLLE (head and lateral line erosion) over time — the pitted, discolored skin that marks a fish maintained on an inadequate diet.

Scientific name: Paracanthurus hepatus
Origin: Indo-Pacific — branching coral zones and reef crests from East Africa to the Pacific, especially common in the Philippines, Indonesia, and the Coral Triangle
Water parameters: Temp 74–82°F · Salinity 1.023–1.026 · pH 8.1–8.4
Tank requirements: 125 gal minimum; 180+ gal preferred; needs extensive swimming room and rockwork refuge
Diet: Herbivore — nori seaweed and algae-based foods must form the majority of the diet; supplement with meaty foods
Compatibility: Semi-aggressive with other tangs; reef safe; provide adequate space to prevent territorial conflict
Husbandry note: Cover open-top tanks. Blue Hippo Tangs jump at high speeds with essentially no warning and will find any gap in screening. This is not a theoretical risk — it’s the most common sudden death cause for this species in home aquariums.