The celestial pearl danio (CPD) is a delightful nano fish often sought by aquascapers because they look like miniature brook trout swimming amid a forest of plants and driftwood. Their beauty and elegance seem to automatically elevate any tank they live in. However, they sometimes get the reputation for being shy fish that are easy to stress. Find out how to care for these enchanting creatures and make them feel right at home.
What are Celestial Pearl Danios?
Danio margaritatus goes by many common names, such as galaxy rasbora and celestial pearl danio, because of the striking golden spots scattered on their dark bodies. They grow up to 1 inch (2.5 cm) long and feature bright, red-orange fins with black striping. Discovered in 2006, they come from Southeast Asia and live in shallow waters with dense vegetation.
How many celestial pearl danios should be kept together? As a schooling fish, they feel most comfortable in large groups so that they can more easily elude predators, find food, and breed. The rule of thumb for schooling fish is to get at least six fish of the same species, but we strongly suggest buying 10-15 CPDs since they can be a bit timid.
When it comes to schooling fish like galaxy rasboras, the more the merrier.
Are celestial pearl danios aggressive? No, CPDs are peaceful nano fish that do well with other community fish. However, they are still danios, which are known for chasing each other to establish dominance or display breeding behavior. Not to worry — while they may do some fin nipping amongst their own species, they rarely go after other tank mates.
How to Set Up an Aquarium for Galaxy Rasboras
We like keeping CPDs in at least 10 gallons of water, but if you purchase a bigger school of 10-15 fish as recommended, go for a 20-gallon aquarium or larger. They can handle a fairly wide range of pH from 6.6-8.0, as well as soft to moderate water hardness (or GH). Because of their chasing behavior, try adding lots of live aquarium plants for them to dart in between.
Are celestial pearl danios cold water fish? While they can live up to 78°F (26°C), they thrive in lower temperatures from 72-76°F (22-24°C). Depending on how warm your home is, you may be able to keep this species in an unheated aquarium without a heater.
Many danios, including CPDs, enjoy cooler temperatures than your average tropical fish.
What fish can you put with galaxy rasboras? Avoid any large fish that may eat, bully, or outcompete them for food. In fact, since CPDs sometimes like to hide, consider adding some dither fish that can encourage them to comfortably swim out in the open. We have kept them with other friendly community fish, such as small tetras, Corydoras catfish, and kuhli loaches. People have had varied results with cherry shrimp as tank mates, so if you try them, make sure to add plenty of hiding spots and expect the CPDs to predate on any baby shrimp they find. Betta fish may or may not work because they tend to prefer warmer waters and can be hostile toward intruders. They may be able to go together if the temperature is kept at 77-78°C (25-26°C), the aquarium is large enough, and the betta isn’t too aggressive.
What do Celestial Pearl Danios Eat?
Since they like to swim in the middle of the tank, try feeding tiny, slow-sinking foods in the water column. Their favorite meals include baby brine shrimp, frozen cyclops and daphnia, and micro worms. As for dry, prepared foods, we like to use crushed flakes and Easy Fry and Small Fish Food. The key is to offer a variety of foods to make sure they get all the necessary nutrients to live a healthy life.
How to Breed Galaxy Rasboras
Celestial pearl danios are relatively easy to breed at home as long as you have at least six fish to ensure there are both males and females. They are egg layers that prefer to spawn in media, so provide dense plants like java moss or a DIY yarn spawning mop. Feed them well, and once the females start developing large bellies full of eggs, they will likely spawn almost every day. In order to prevent the adults from snacking on their own eggs, move the spawning media into a separate tank and the eggs should hatch within a week, depending on the water temperature. Another method is to place the galaxy rasboras in an outdoor mini pond with plenty of aquatic plants during warmer seasons and bring them back inside at the end of the summer to see how much they have multiplied.
Male celestial pearl danios (above) are more brightly colored, while females are rounder in shape.
Newborn CPDs are very tiny and require fry food that is less than 50 µm in size, such as infusoria, green water, and vinegar eels. Once they are large enough, we highly recommend feeding them live baby brine shrimp because they are packed with healthy fats and proteins to help the fry grow quickly.
Given how beautiful celestial pearl danios are, it’s no wonder that they have become so popular with keepers of nano planted tanks. For more stocking ideas, check out our article on the Top 10 Stunning Nano Fish for Your Next Small Fish Tank.