CARE GUIDE FOR CELESTIAL PEARL DANIOS
Celestial pearl danios (Danio margaritatus)
Celestial pearl danios (Danio margaritatus), often called galaxy rasboras or CPDs, are super cool nano fish that you’ve probably seen at some stage while walking through aquarium stores. They are really pretty fish that resemble mini trout in a lot of ways. While these fish are super easy to keep and breed there are a few important things you should know about them before you get a nice big group. Things that no one ever talks about.
Celestial Pearl Danios Tank Setup
Tank Size: Start with at least a 10-gallon tank for six CPDs, but if you can try to get a school between 10-15 for the most activity and behaviour.
CPD TANK Parameters
Temperature: 72–76°F (22–24°C); can go up to 78°F.
PH: 6.5–7.5.
Hardness: Soft to moderately hard water.
Tank Design: Dense live plants, driftwood, and floating plants provide hiding and breeding spaces. These fish actively explore from the tank bottom to the water’s surface. They aren’t the biggest fan of bright lights so floating plants will help them become less shy.
Lighting: Moderate; subdued lighting can enhance their colours and reduce stress.
Filtration: Use low-flow filters to avoid disturbing their preferred calm waters.
CPD Behavior and Social Needs
CPDs are highly active and super social fish. A minimum of six fish is recommended, but 10-20 will give you more natural behaviours and reduce stress.
Male celestial pearl danios sparing each other.
Activity: These boisterous fish constantly explore all tank levels, often interacting with plants and tankmates.
Jumping Risk: CPDs can and will jump out of the tank, especially during spawning. Ensure water levels are a few inches below the rim, or use floating plants or a lid to reduce this risk
Tankmates: Ideal companions are similar sized nano fish but I’ve had the most success with pygmy cories, shrimp and snails. However, CPDs will actively hunt shrimplets, shrimp need dense hiding spaces to coexist peacefully. In most cases, shrimp will outbreed a population of CPDs if you have enough density in the tank.
Note: Celestial Pearl Danios aren’t entirely shrimp safe and are masterful little shrimp snipers.
My latest CPD & Shrimp Aquascape
CELESTIAL pEARL dANIO Feeding
CPDs are midwater feeders with a preference for small, slow-sinking foods. A diverse diet ensures health and vibrancy:
Live/Frozen Options: Baby brine shrimp, daphnia, and cyclops.
Prepared Foods: Crushed flakes, micro-pellets, or specialty fry foods.
common cpd Health problems
CPDs are generally hardy but prone to some health issues:
Dropsy (Pineconing): A condition caused by kidney failure, often linked to infections or chronic stress. Symptoms include bloating and scales sticking out like a pinecone. Early intervention with improved water quality and antibacterial treatments may help
Wasting Illness & Sunken Bellies: One of the biggest issues with CPDs is that they are overbred and often really inbred so they are prone to deformities. They are also quite susceptible to wasting caused by internal parasites so avoid any fish that you see with sunken bellies.
cELESTIAL pEARL dANIO Breeding
CPDs are egg layers that spawn readily in planted tanks:
Spawning Setup: Use java moss or spawning mops for egg deposition.
Egg Protection: Adults will eat their eggs if they can find them. If the eggs do hatch they’ll eat the fry pretty quickly, so transferring the eggs to a separate tank improves fry survival rates.
Fry Care: Start with microscopic foods like infusoria, transitioning to baby brine shrimp as they grow. I’ve also had a lot of success with powdered fry food.
The best CPD breeding system I’ve seen.
Conservation History
CPDs nearly faced extinction soon after their discovery due to overcollection for the aquarium trade. Initially thought to inhabit a single habitat, their popularity led to severe overharvesting. Efforts to establish captive breeding programs and locate additional populations in Myanmar have been successful, helping reduce pressure on wild stocks