Looking for a small but colorful fish to add some life to your shrimp tank or peaceful freshwater community aquarium? The tiny phoenix rasbora (scientifically known as Boraras merah) may be just what you've been looking for.
Below, let's have a look at everything you need to know about phoenix rasboras, including where they're from, what you need to keep them, and what they eat.
Although you need to get pretty close to really get a good look at the teeny tiny phoenix rasbora, this is a very nice fish to look at. It grows to a maximum size of a little under an inch and sports a deep red body color with orangeish and black markings. In fact, the denomination " merah " is a reference to the Indonesian word for "red".
It can be quite different to tell the difference between a phoenix rasbora and its close cousin the chili rasbora, scientifically known as Boraras brigittae . The black coloration on the former tends to be more blotchy, though, and it has less red coloration. Still, even scientists have wondered whether they could be one and the same!
As is usual with fish, the males of this species are more brightly colored than the females. Healthy males will be a striking ruby red.
This species is naturally found in the Indonesian part of the island of Borneo (known as Kalimantan). It pops up in large schools in the southern and western parts of the island, where it inhabits slow-flowing, swampy blackwater forest streams and rivers.
Due to the large amounts of leaf litter and high peat content, the water in these habitats is stained a dark color (hence "blackwater"). These factors also cause very low water hardness and acidity.
The IUCN Red List lists Boraras merah as a "Data Deficient" species, but it does note that the wild population unfortunately appears to be on the decline. Peat swamp forests in Borneo are under serious threat of deforestation for agricultural purposes (like palm plantations) and urbanization. Overfishing for the aquarium trade is also an issue.
Thanks to their size, a group of phoenix rasboras doesn't need a lot of space. Still, they're not suitable for the tiniest nano tanks either, as they can be quite active. A 10 gallon long aquarium would be the minimum for 6-8 individuals, but bigger is better.
Although you don't have to set up an Indonesian peat swamp biotope aquarium, your phoenix rasboras will appreciate it if you try to at least keep their natural habitat in mind. Between fallen debris, dark water and the forest canopy blocking out the sun, they aren't used to bright lighting. The waters they inhabit are relatively sluggish, so don't use an overly powerful filter.
Use twigs, leaf litter and aquatic plants to give the tank a natural feel and so the fish have some cover. Floating plants with their long roots work particularly well for this. A dark substrate is probably preferable.
As always, the aquarium you want to keep your phoenix rasboras in should be filtered and fully cycled . It should also have a heater, as this species hails from tropical regions and needs a stable temperature between 68-82.5 °F.
Aside from these basic requirements, it's important to keep in mind that your phoenix rasboras won't thrive in hard water with a high pH. The water in their natural habitat can have a pH as low as 4 (which is quite extreme!) and negligible hardness.
Because this species doesn't deal well with water quality swings, it's important to stay on top of regular aquarium maintenance. Weekly small water changes with temperature-matched water are important.
Temperature: 68-82.5 °F
Hardness: max. 100 ppm
Like most small schooling fish species, phoenix rasboras mostly inhabit the middle water layer. They can be combined with other calm, peaceful species that thrive in similar water parameters. Choosing fish and invertebrates that inhabit the bottom and top water layers would work well.
Examples of suitable phoenix rasbora tankmates include:
Fellow shrimp enthusiasts will also be happy to hear that phoenix rasboras play nice with dwarf shrimp. As always, it's never a good idea to combine any fish with your most fragile or expensive shrimp, as they will eat newly hatched fry if they get the chance.
Still, populations of red cherry shrimp or crystal reds should be absolutely fine alongside these small rasboras, especially if you add some Java moss for the babies to hide in. Amano shrimp and other larger species should also work well.
You should avoid adding larger, carnivorous or overly boisterous species to your rasbora tank. Angelfish and other cichlids will view them as snacks.
Did you know? You should ideally keep 10+ (ideally 20 or more) phoenix rasboras. They'll be less skittish and it's a joy to see the males displaying their beautiful colors and fins for the females!
Your phoenix rasbora starter pack:
In the wild, phoenix rasboras are both predator and prey. Like other rasbora species, they're assumed to be mostly carnivorous, eating small (aquatic) bugs, worms and larvae.
What you feed your phoenixes in the aquarium should reflect this. Although they will probably accept microflakes or -pellets, it's a good idea to also offer them plenty of frozen and live foods. Things like brine shrimp, Daphnia, microworms and the like will be much appreciated.
If you have a large, densely planted aquarium without much in the way of predators, you may find your phoenix rasbora population expanding by itself. If this is not the case, or things aren't going quickly enough for you, you can also set up a dedicated breeding tank. This species breeds readily in captivity, although it is a bit of a finicky affair given their size!
Everyone has their own favorite methods for breeding aquarium fish, but the following should work well for phoenix rasboras and other members of the genus Boraras. They're egg scatterers that don't display any parental care.
→ Learn all about breeding egg-scattering fish
The genus Boraras is quite popular in the aquarium hobby due to its small size. Most aquarium stores should stock some of these rasboras. You can also buy them online: The Shrimp Farm sells phoenix rasboras and ships them right to your doorstep with live arrival guarantee!
Kottelat, M. (2013). The fishes of the inland waters of Southeast Asia: a catalogue and core bibliography of the fishes known to occur in freshwaters, mangroves and estuaries. Raffles Bulletin of Zoology .