Lightly Medicated | Celestial Pearl Danio (Danio margaritatus)

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 3–5 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 two and a half 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.

The Celestial Pearl Danio (Danio margaritatus) wasn’t formally known to science until 2006 — formally described from a single locality in Shan State, Myanmar — making it one of the more recent entries to the aquarium trade and a species that went from scientific discovery to widespread captive breeding in a matter of years. That dark blue-black body covered in small gold spots, with orange-red banded fins on males that deepen during displays, looks genuinely more like a piece of jewelry than a fish, which explains the rapid adoption.

Despite the fragile appearance, they’re genuinely hardy once established in appropriate conditions — the fragility reputation largely traces to newly-imported wild specimens before captive breeding stabilized the trade. Tank-raised D. margaritatus adapt readily to standard soft-to-moderately-hard freshwater and eat eagerly. Males intensify their colors dramatically during courtship displays, flaring fins at rivals and females in a way that shows off that banded pattern to full effect.

They’re best kept in groups in a heavily planted nano tank. The planted environment and subdued lighting actually enhances the spotted pattern — under bright, bare-tank conditions, the spots read as pale and the fish looks washed out. More plants, darker substrate, lower light, bigger group.

Scientific name: Danio margaritatus
Origin: Shan State, Myanmar — shallow, clear, heavily vegetated ponds and pools at highland elevation
Water parameters: Temp 68–78°F · pH 6.5–7.5 · GH 5–15 (adaptable; prefer moderate hardness)
Tank requirements: 5–10 gal minimum; planted nano tank; groups of 8–12+ recommended
Diet: Omnivore — micro-pellets and small flake; supplement with baby brine shrimp, daphnia, and micro-worms
Compatibility: Peaceful nano fish; must be kept with equally small, non-predatory species
Husbandry note: Males competing for females is where the color display peaks — a group of 8+ with a slight male-to-female bias of 1:2 produces the most consistent display behavior and the best looking tank.