Celestial pearl danio facts for kids
Quick facts for kids Celestial pearl danio |
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| Adult male | |
| Conservation status | |
| Scientific classification | |
| Genus: |
Danio
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| Species: |
margaritatus
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| Synonyms | |
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Celestichthys margaritatus Roberts, 2007 |
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The Danio margaritatus, also known as the celestial pearl danio, is a tiny, colorful fish. People who keep fish often call it the galaxy rasbora. This small fish comes from Myanmar and Northern Thailand. It was first found in 2006 near Inle Lake in Myanmar. This area is high up, over 1,000 meters (3,400 feet) above sea level.
The celestial pearl danio quickly became popular in the aquarium hobby. Its small size and bright colors made it a favorite.
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Description
This fish is small and a bit plump. It has a blunt snout and usually grows to about 2 to 2.5 centimeters (about 1 inch) long. Some can even reach 3 centimeters. Its body is about three times longer than it is tall. It looks a lot like another fish called Danio erythromicron.
Males and females of this fish look a little different. This is called sexual dimorphism. Males have a bright blue body color. Females are more of a dull blue-green. The fins of the males are also much brighter. The part of their body near the tail (called the caudal peduncle) is taller in males than in females.
The fish's body is covered with small, shiny, pearl-like dots. Its back is a bronzy green color. The belly of females is yellowish-white. You can see the blood-red gills through their clear gill covers.
When males want to attract a mate, they show off their fins. Most of their fins have two black lines with a bright red area in between. On the tail fin, this pattern appears twice. Females have a weaker version of this pattern, mostly on their tail and dorsal fins.
A male ready to mate will get a red belly. His sides will also become brighter and darker. This makes his pearly spots stand out even more. A female ready to lay eggs has a black spot near her anus. This spot separates her belly color from the reddish base of her anal fin.
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Male
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Male
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Female
Systematics and Taxonomy
When the celestial pearl danio was first found, scientists thought it belonged to the Microrasbora group of fish. This was because it looked similar to "Microrasbora" erythromicron. Less than a year later, it was officially named Celestichthys.
However, in 2008, more studies showed that the celestial pearl danio actually belongs to the Danio group. Its closest relatives are Danio erythromicron and Danio choprae.
Ecology
The celestial pearl danio lives in small ponds. These ponds are made by groundwater seeping up or by small streams overflowing. In January, the water temperature is cool, about 22–24 °C (72–75 °F). But because these ponds are very shallow, they can warm up quickly when it's hot. This means the fish can probably handle temperatures above 26°C (79°F).
Like most water in the Inle area, the water is a little bit alkaline. The fish's home is full of plants, especially water weeds similar to Elodea.
The celestial pearl danio shares its home with only a few other fish species. These include a type of Microrasbora, a rosy loach, and the dwarf snakehead Channa harcourtbutleri. The dwarf snakehead is likely the main predator of the celestial pearl danio.
Local people sometimes catch these fish for food. They dry them and sell them as a protein source. Before the fish became popular for aquariums, a can of about 500 fish sold for a very low price.
Reproduction
The celestial pearl danio lays eggs in a special way. This is important for people who want to breed them in aquariums. This fish seems to be good at living in small ponds that might dry up sometimes. It doesn't have a specific time of year when it lays eggs. Females also don't lay eggs all the time. Instead, they lay small groups of about 30 eggs at once. We don't know how long they wait between laying eggs.
The eggs are not just dropped into the water. They are also not stuck to a prepared surface. Instead, the fish seems to hide them loosely in plants. Males looking for a mate will try to find and protect a patch of thick plants. When a male and female are ready to mate, they move into the plants and lay the eggs. Other males might try to follow them to fertilize or eat the eggs.
At temperatures of 24–25 °C (75–77 °F), the larvae hatch after 3 to 4 days. They are dark and hard to see at first. For about three days after hatching, they hide among plants and dirt. After this, they become lighter in color and start swimming and eating on their own. About 8 to 10 weeks after hatching, they change into their adult form. Their colorful pattern starts to show up around 12 weeks old.
Status and Conservation
Soon after the celestial pearl danio became popular in aquariums, there were false reports. People said the fish had become very rare in the wild. At first, only a few aquarists could breed the fish. This meant most fish sold were caught from the wild.
People worried about the wild populations. A British fishkeeping magazine even asked people to only buy the fish if they planned to breed them. This was to help reduce the demand for wild-caught fish. Since the fish lives in small ponds that might disappear, it was thought they couldn't handle too much fishing. If all fish were caught from a pond, it was unclear if they could come back. However, if only some fish were removed, the ponds could likely get a healthy population again after about a year.
The serious warnings turned out to be wrong. The celestial pearl danio reproduces very quickly, almost every day. Ponds that seemed empty would be full of fish again a few months later. This is because the young fish hatched, grew, and reproduced fast.
The government of Myanmar stopped exports of the fish in February 2007. However, officials in Myanmar found populations of the fish in at least five places around Hopong. Today, many people around the world breed this fish in aquariums. This has made the price much lower than it was when it first became popular.
In the Aquarium
The celestial pearl danio is not a difficult fish to keep if you meet its basic needs. It doesn't need a huge tank because it's not a very active swimmer. It also doesn't need a large group of its own kind to be happy. In a small tank, a group of six fish, with half males and half females, will do well. They will show their natural behavior. They often stay still, hovering in their favorite spots. Males and females tend to stay separate when resting. Their behavior is quite similar to Danio erythromicron.
Tanks for celestial pearl danios should have many plants. Direct sunlight might even be good for them, as their natural home is shallow and well-lit. Water weeds and similar plants should be plentiful. You should also add stones and wood to create places for them to hide. It's a good idea to give the fish a spawning mop or a thick growth of plants like java moss for them to lay eggs in. A dense tangle of natural plants also has tiny living things that the young fish (called fry) can eat when they first hatch.
The celestial pearl danio is generally peaceful. However, they might nip at the fins of other fish sometimes. Because of this, you shouldn't keep them with very large or "bully" fish. Other small, active danios that like similar water conditions would be a good choice for tank mates. These more active fish create a nice contrast. They also come in many colors and patterns, so you can choose fish that look good with the bright colors of the celestial pearl danio. Many danios prefer slightly acidic water. However, it's important to keep the water somewhat alkaline for fish from the Inle basin, as that's what they are used to.
Images for kids
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Adult female
