Phoenix Rasbora Care: Size, Food, School Size & Tank Size

Scientific NameBoraras Merah
Common NamePhoenix Rasbora
OriginSouthern Borneo
Water pH4.0-7.0
Adult Size0.5 to 0.8 inches
DietCarnivorous but will eat an omnivorous diet

Phoenix Rasbora Facts

  • Phoenix Rasboras get the scientific name Merah from the Indonesian word meaning ‘red.’ This is a reference to the Phoenix Rasbora’s striking red coloration.
  • Phoenix Rasboras are nano schooling fish, and they are among the smallest fish in the aquarium hobby. They only grow to 0.5 to 0.8 inches at full maturity.
  • Phoenix Rasboras are often mistaken for other types of Rasboras. Be sure to correctly identify Rasboras before you purchase them at the local fish store. You can also find many retailers online who are selling Phoenix Rasboras.
  • Phoenix Rasboras are egg scattering fish. After spawning, they will not look after it. In fact, if given the opportunity, they will consume their own eggs and fry.

Phoenix Rasbora Care

Phoenix Rasboras are vibrantly colored and active nano schooling fish. They are often misidentified because they are marked very similarly to other Rasboras. Phoenix Rasbora has black spots on its body and has a bright orange-red around each one. The bright orange-red coloration connects together, and extends towards the head. The vibrant coloration is only present around the black spots of the fish, and the rest of the body of the Phoenix Rasbora is a dullish grey color that fades into a transparent color towards the fins. The fins have some red markings at the ends. The black spot in the middle of the body is much darker than in other Rasboras. In addition, Phoenix Rasboras lack the black line that runs along the body of other Rasboras.

phoenix rasbora
Phoenix Rasbora (Boraras merah)

Female Phoenix Rasboras can be distinguished from the males because they have a much larger black spot in the center of their bodies. It is much easier to identify the males from the females when they are mature. The females will have a rounded body shape, especially when they are carrying eggs. In comparison, the males will usually have a slimmer body. Their body may display a darker red color, especially when they are ready to spawn.

Food and Diet

Phoenix Rasboras prefer a carnivorous diet, and they are described as a micropredator. In the wild they survive on eating small insects, worms, tiny crustaceans, and zooplankton. They will also scavenge through plant matter and vegetation at the bottom as well. In captivity, they will readily accept dried foods, but this should not be their only food source. Daily meals of live and frozen foods such as Daphnia are a great food to add to their diet. Adding these treats in addition to their flakes and pellets will help bring out their brightest colorations, and encourage them to spawn.

One of the biggest challenges of feeding your Phoenix Rasboras is finding them food that is small enough to fit in their mouths. Small live invertebrates are a great options for this. Microworms, mosquito larvae, and small bloodworms are among their favorites. Frozen foods are also an option for feeding, but they will need to be thawed and finely chopped into small enough pieces for them to be able to eat. Phoenix Rasboras do best when they are fed two times a day.

Tank Size & Tank Requirements

Phoenix Rasboras are among the smallest of the Rasbora genus. A 5 gallon tank can house a school of no more than 6 Phoenix Rasboras. You will want to add at least an additional gallon for each 2 fish you add to their school after that.

When it comes to setting up a tank for Phoenix Rasboras, you will want to set up a tank that closely mimics their natural habitat. Phoenix Rasboras come from the wilderness of Borneo. They often inhabit black water streams that run into peat swamps. These blackwater streams are densely planted with vegetation, and this provides a low level light environment with plenty of places to hide.The decaying organic matter releases beneficial tannins into the water, and their substrate is strewn with branches and fallen leaves. They are the happiest in low level lighting as it mimics the forest canopy that shades the rivers and streams.

Phoenix Rasboras will inhabit the middle and top of the aquarium most of the time. However, they will visit the bottom to scavenging for food as well. You will want to make sure that there are adequate places for them to hide and destress if they need to, especially if you have other species of fish in your aquarium.  

Size and Lifespan

Phoenix Rasboras are among the smallest nano schooling fish, reaching only about 0.5 to 0.8 inches at full maturity. They can live for up to 7 years if they are properly cared for. Like other nano schooling fish, Phoenix Rasboras are sensitive to large water changes. Therefore, when you are cleaning your tank, you will want to do smaller, more frequent water changes.  Large water changes should be avoided since it can shock them.

Schooling Behavior & School Size

Phoenix Rasboras are nano schooling fish that are the happiest when they are together in a large school. They are able to display all their natural behaviors when they are in a group. The minimum number of Phoenix Rasbora in a school should be 6 or more. Ideally, they do best in schools of 20  or more. Phoenix Rasboras are an active fish that are a joy to watch. The more Phoenix Rasboras that you have in your school, the more you will see these schooling behaviors in your aquarium. When kept in a bigger school, Phoenix Rasboras may also begin to spawn. If the conditions are right for the fry, they may be able to grow in the tank. You may occasionally notice new fish joining the school as the juveniles become large enough.

Do Phoenix Rasboras do well with Bettas?

Phoenix Rasboras and Bettas both thrive in the similar water parameters. In fact, they coexist in the same geographic region in the wild. As micropredators originating from the same region, they also have very similar feeding requirements.

If you are planning on keeping Phoenix Rasboras and Bettas together, you will want to make sure that they have enough room. Bettas can be territorial fish, and this is especially true for male bettas. Phoenix Rasboras can also display some territorial behavior during spawning. It is a good idea to make sure that there are enough places for them to hide and destress from one another. It is also a good idea to monitor your fish for changes in behavior when you introduce fish into your aquarium.

Besides betta fish, there are other fish that can coexist with Phoenix Rasboras. When it comes to choosing tank mates with your Phoenix Rasbora, the general guideline is to choose fish that is similar in behavior. Phoenix Rasboras are active fish, but mostly docile in terms of their temperament. They will usually not bother other fish in your aquarium.

Phoenix Rasbora VS. Chili Rasbora

Phoenix Rasboras are often mistaken for Chili Rasboras because of their similar colors and patterns. Phoenix Rasboras have more black spots on their bodies, and they have more red on their fins. Chili Rasboras are more brightly colored on their bodies. Chili Rasboras have more orange coloration when compared to the reddish color of the Phoenix Rasbora.

Both Phoenix Rasboras and Chili Rasboras are nano schooling fish that are very popular in the aquarium hobby. They are both known for their active personalities and their bright colorations. They are similar in many ways, including their water parameters, diet, behavior, and even spawning patterns.

Phoenix Rasbora Breeding and Eggs

When Phoenix Rasboras are ready to spawn, you may notice the males developing a darker coloration. Phoenix Rasbora females will become more rounded and slightly larger once they are full of eggs. Phoenix Rasboras are egg scattering fish. The females will scatter their eggs on the bottom of the aquarium for the male to fertilize. Phoenix Rasboras do not care for their young, and they may even try to eat the eggs and fry.

If you want to breed your Phoenix Rasboras or get a higher yield of fry, you may want to set up a dedicated breeding tank so that you can remove the adults away from them after spawning. If you notice that your Phoenix Rasboras are not spawning, you can feed them a higher protein diet with live foods to condition them. Lowering the lighting in your aquarium may help encourage them to spawn as well. The right amount of dimness will allow them to relax.

Phoenix Rasboras will continually spawn if they are kept in the right conditions. If they are in a heavily planted tank, you may notice some of the fry eventually joining the school even without human intervention.

Once the eggs have been fertilized, you will notice the eggs hatching around day two. Once they hatch, the tiny fry will stay attached to the yolk of their egg for another 24 hours. After a day, they will require tiny live foods to survive. After about 7 to 10 days, the fry will be large enough to accept slightly larger foods. Although water quality is very important for the health of the fry, drastic water changes should be avoided. Large water changes can shock the fry, especially for the first few weeks. This is when they are the most sensitive.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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