Known for their small size and striking appearance, the Celestial Pearl Danio (CPD) is a popular nano fish. These active little fish look like Brook Trout in miniature, with their dark bodies scattered with golden spots. CPDs can be shy, so it’s best to keep them in sizeable schools with 10–15 of their own kind. This also increases the likelihood of breeding.
Here’s a look at how to breed Celestial Pearl Danios in a handy step-by-step guide.
1. Set Up and Cycle Your Aquarium
Also known as Galaxy Rasboras, Celestial Pearl Danios are a great fit for nano tanks since they only grow up to 1 inch in length. A minimum tank size of 10 gallons is recommended, but if you’re hoping to breed your fish, a larger 20-gallon tank might be better. This enables you to start with a larger school of fish and gives you room to accommodate growing fry.
Because CPDs are timid fish, they’ll appreciate having plenty of cover in their tank. A tank filled with vibrant aquarium plants creates an ideal environment, particularly when including floating species with long roots. The roots will help break up sightlines to reduce aggression between males and will provide cover for newly hatched fry.
Here’s a quick overview of the ideal tank parameters for Celestial Pearl Danios:
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Tank Size: Minimum 10 gallons (ideally 20+)
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Temperature: 72°F to 78°F
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pH Level: 6.5 to 7.5
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Water Hardness: 1 to 5 dGH
When setting up your nano tank, aim for long-term stability. Proper filtration is essential, but you want to avoid anything too strong that might put newly hatched fry at risk. Depending on the climate where you live, you might not need to heat the tank, but using an aquarium heater helps keep the water temperature consistent.
Once you’ve set up your tank, give it plenty of time to cycle before adding your fish. If you’re planning on raising the fry in the same tank as the adults, it doesn’t hurt to add some driftwood, catappa leaves, or porous rock to start cultivating biofilm and populations of microfauna for the fry to feed on.
2. Add Spawning Media
Celestial Pearl Danios are egg scatterers, so you’ll need to add some kind of spawning media to your tank to catch the eggs. If you’re going for a natural look, Java moss works very well for this purpose, and it grows fairly quickly. You can also purchase spawning mops to add to your tank.
As you’re choosing spawning media for your CPD tank, consider what the fry will need as they hatch and develop. Cultivating a lush carpet of Dwarf Hair Grass, Dwarf Baby Tears, or something similar will give the fry places to hide and hunt for food.
3. Introduce Your Celestial Pearl Danios
Once your tank has fully cycled, it’s time to introduce your fish. The best method is slow drip acclimation; it’s a gradual process that helps minimize stress for your fish.
Here’s how to do it:
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Transfer your fish to a small bucket or container along with the water from the bag.
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Run a length of airline tubing from the aquarium to the bucket.
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Tie a loose knot in the tubing and start a siphon to get the water flowing.
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Tighten the knot (you can also use an airline control valve) until the water is dripping at a rate of about one drop per second.
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Let it drip until the water volume in the bucket has at least doubled.
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Carefully net the fish and transfer them to the tank, and discard the water in the bucket.
Celestial Pearl Danios can be sensitive fish, so it doesn’t hurt to give them a little extra time to acclimate. At a minimum, use the drip method for 30 minutes, but consider extending the time up to 2 hours as long as there’s no risk of the water temperature dropping significantly during that time.
4. Condition the Fish
When your Celestial Pearl Danios are happy in their new home, the next step is to start conditioning them for breeding.
CPDs are omnivores, so they’ll accept a wide variety of fish foods, including crushed flakes and micro pellets. Supplement a commercial diet with live, frozen, and freeze-dried foods like baby brine shrimp and daphnia.
The key to conditioning fish for spawning is to keep the conditions in their tank stable with regular aquarium maintenance while providing a nutritious, protein-rich diet. Instead of feeding your CPDs once a day, offer several small meals daily. When using frozen foods, be sure to thaw the food in a cup of tank water before offering it to your fish.
5. Watch for Spawning Behavior
As you’re conditioning your Celestial Pearl Danios, start monitoring them for breeding behavior. If you’re starting with juvenile fish, it may take them time to mature, but once they do, you may be able to distinguish the males from the females.
Males tend to be smaller and slimmer than females. When they’re sexually mature, males also tend to develop more vibrant color and bright red markings. Female CPDs have slightly duller coloration and more rounded bodies. As they become sexually mature, they will develop a black spot near the anal fin.
When you see the males start to chase the females around the tank, it’s a sure sign of spawning behavior. Male CPDs perform a sort of courtship dance in which they aggressively follow the female with their heads down, displaying their head stripes and colorful fins. The male will guide the female to the spawning site, then the two will entwine, the female releasing her eggs as the male fertilizes them.
6. Separate the Adults from the Eggs (Optional)
Celestial Pearl Danios don’t display parental care, so there’s some risk of predation by the parents if you don’t remove them from the tank after spawning. The spawning media should, however, provide some cover as the eggs develop and start to hatch. You can remove the adults from the tank, if you like, but it’s not always necessary to do so.
If you choose to raise the fry separately from the adults, make sure you have a separate tank set up and matured to accommodate the adults. It’s also important to ensure that any filtration you have set up in the fry tank won’t put them at risk. Sponge filters are ideal for rearing tanks.
7. Raise the Fry to Maturity
CPDs tend to have small spawns, only about a dozen eggs each. Because they’re so small, it may be difficult to see your Celestial Pearl Danio eggs, especially if they’re embedded in spawning media.
After 2–4 days, the eggs will hatch and the fry will become free-swimming over the next day or two. Newly hatched Celestial Pearl Danio fry can generally feed on infusoria and other microfauna in the tank until they’re large enough to accept the same foods as the adults.
If you’re breeding multiple females at once, however, it doesn’t hurt to add some powdered fry food or baby brine shrimp to the tank to give the fry something to feed on. With adequate nutrition, the fry should grow quickly and soon be ready to accept traditional foods.
Now that you know how to breed Celestial Pearl Danios, maintaining proper care is just as important. Ensuring stable tank conditions, a balanced diet, and a stress-free environment helps your fish thrive. Following a proper Celestial Pearl Danios care guide keeps them healthy, active, and vibrant.
Wrapping up
Breeding and caring for Celestial Pearl Danios can be rewarding, but questions may arise along the way. For everything you need to create and maintain a thriving tank, from aquarium plants to specialty foods and essential supplies, Shrimpy Business offers a wide selection trusted by aquarists.
If you need guidance or support with your aquarium setup, contact us, and we will be happy to help your fish stay healthy and active!