Celestial Pearl Danio

1) Where they come from (the quick story)

Celestial Pearl Danios (aka Galaxy Rasboras) come from small, plant-choked ponds and slow waters in Myanmar. Think shallow margins, lots of cover, and calm water—not big open rivers. That background explains basically everything about how they act in our tanks: they like plants, they spook easily, and they don’t love getting blasted around by strong flow.

2) Setting up their tank

If you want to actually see these fish instead of having them live in permanent “hide mode,” give them a tank that feels safe. Dense plants, darker substrate, and some broken sight lines make a huge difference.

• Tank size: 10 gallons works for a small group, 15–20 gallons is where they really start showing natural behavior
• Group size: aim for 8–12+; in smaller groups they’re shy and bicker more
• Plants: go heavy—stem plants, crypts, moss, floating plants; a little jungle is your friend
• Hardscape: small wood/rocks to create pockets and “lanes” between plant clumps
• Flow: gentle to moderate; a sponge filter or a baffled HOB is perfect
• Lighting: medium or even slightly dim (floating plants help a lot)
• Cover: tight lid—these little guys can jump, especially when spooked

Water-wise, they’re not super fragile, but they don’t love sudden swings. I’ve had the best luck keeping things stable and clean rather than chasing a perfect number. Mid-60s to mid-70s °F (18–24°C) is a comfortable range, and they often color up nicely on the cooler side.

3) What to feed them

They’ve got tiny mouths, and a lot of them ignore big flakes like they’re not even food. Once you feed appropriately sized stuff, their personality changes—more activity, better color, and less skittishness.

• Daily staples: micro pellets (0.5 mm-ish), crushed high-quality flake, baby granules
• Favorite “make them pop” foods: baby brine shrimp, daphnia, cyclops
• Frozen options: frozen cyclops, finely chopped bloodworms (sparingly), small frozen daphnia
• Feeding style: small portions 1–2x/day; they do better with frequent tiny meals than one big dump

4) Behavior and tankmates

CPDs are peaceful, but the males definitely posture and “spar.” It’s more like a dance than a fight—flaring fins, chasing for a second, then back to hovering. In a planted tank with a decent group size, it stays interesting instead of stressful.

• Best vibe: species-only or a calm nano community
• Good tankmates: small rasboras, ember tetras, chili rasboras, small peaceful loaches, otocinclus, shrimp (with caveats)
• Use caution: bigger/fast fish like zebra danios, larger barbs, or anything that hogs food
• Avoid: aggressive fish, fin nippers, and anything that sees tiny fish as snacks

Shrimp note: adults usually coexist fine, but baby shrimp are basically popcorn. If you want shrimp reproduction, give the shrimp a dense moss pile and lots of hiding spots—or keep CPDs in a separate tank.

5) Breeding tips (fun and very doable)

Breeding CPDs is one of the more rewarding “intermediate” projects because they’ll spawn pretty readily… but the adults and basically everything else will eat the eggs. So the trick is egg protection, not convincing them to breed.

• Conditioning: feed live/frozen foods for 1–2 weeks (baby brine shrimp works wonders)
• Spawning setup: a clump of Java moss, a spawning mop, or a mesh/marble bottom so eggs drop out of reach
• Pair vs group: groups work great—more natural, less pressure on one female
• Egg collection: check moss/mop daily and move eggs to a small grow-out container with gentle aeration
• Fry food: infusoria/rotifers at first, then baby brine shrimp once they can take it (they grow faster than you’d think)

6) Common problems to watch for

Most CPD issues I’ve seen come down to stress, food competition, or bringing home weak fish. They’re small, so problems can snowball fast if you miss them for a few days.

• Shyness/hiding nonstop: usually not enough plants/cover, too much light, or pushy tankmates
• Getting skinny even though you feed: food pieces are too big, or faster fish are stealing everything
• Sudden losses after purchase: sensitive to shipping stress + uncycled tank or big parameter swings
• Ich and other common parasites: shows up as white spots, flashing, clamped fins—often after stress
• Internal parasites (sometimes): stringy white poop, weight loss with appetite; quarantine helps a ton

One last practical thing: watch them at feeding time. If you’ve got a couple bold fish getting round and a few staying pinched in the belly, adjust the food size, spread food across the surface, or consider separating the slow eaters for a week. That tiny tweak fixes a lot of “mystery” problems.