Three quarters of an inch, and four sources that disagree
A chili rasbora ties the ember tetra for the smallest fish on this site, and on the two questions a buyer asks first our sources split cleanly down the middle. Two of them put it in acid water and two put it in alkaline. Two call it timid and one calls it bold. Neither split is a rounding error.
The fish itself is not in doubt. Seriously Fish measures it at 20 mm standard length and files it as Boraras brigittae, formerly Rasbora urophthalma brigittae Vogt, 1978. Wikipedia records who it is named for: Dieter Vogt, who described this species, named it in honor of his wife, Brigitte. It also puts the family in a different place, Danionidae against Seriously Fish's Cyprinidae, which is the kind of disagreement that changes nothing about a tank.
Where it comes from is the part that explains the argument. Seriously Fish: it inhabits black water streams and pools associated with ancient forest peat swamps, where the water is stained brown due to the release of tannins and other chemicals, and where the pH runs as low as 4.0. Wikipedia calls the same place the swamps of South West Borneo.
Seriously Fish also carries a sentence no care sheet on this record does, and it is worth printing whole: across much of Southeast Asia these precious biotopes are under threat from rubber or palm oil plantations.
Why this record was written now
- The gap
- Thirteen thousand searches a month, and the fish our ember tetra record is most often compared with had no page here.
- What it changes
- At 18 to 20 mm it ties the ember tetra for the smallest fish here, and its pH row is the first that had to be settled by looking at the wild water rather than at a majority.
- What it does not
- The strawberry and phoenix rasbora comparison. All four sources name other Boraras species and not one of them describes how to tell them apart.
Chili rasbora water parameters: two against two
| Source | Temperature | pH | Hardness |
|---|---|---|---|
| Seriously Fish | 68 to 82 °F | 4.0 to 7.0 | 1 to 10 dGH |
| Aquarium Source | 68 to 82 °F, aim for 74 | 4.0 to 7.0, 6.0 ideal | 3 to 12 dKH |
| Aquarium Co-Op | 72 to 82 °F | 6.0 to 8.0 | Soft to hard |
| Wikipedia | 72 to 82 °F | 6.0 to 8.0 | Soft to hard |
| The wild, per Seriously Fish | not stated | As low as 4.0 | Black water, stained with tannins |
The pH column is a three point disagreement with a one point overlap. The specialist reference and one care site put the fish from 4.0 to 7.0. The largest retailer on this record and the encyclopedia put it from 6.0 to 8.0. Everything both pairs support is 6.0 to 7.0, and that is what the row prints.
What settles the reading is not the count but the breeding advice, because there the two halves converge. Seriously Fish asks for pH 5.0 to 6.5 to spawn it. Aquarium Co-Op, from the alkaline half of the split, says an acidic pH below 7.0 may help improve the hatch rate. Both halves point below neutral to breed the fish, and only one half will go below 6.0 to keep it.
On temperature all four bands contain 72 to 82 °F, which the record carries. Aquarium Source is the only source with a target inside it, and it is a low one: aim for 74 °F if possible.
On hardness the two sources that publish a figure use different units, which this site has now met on four records. Seriously Fish gives 1 to 10 dGH, general hardness. Aquarium Source gives 3 to 12 dKH, which is carbonate hardness. Taken as published they overlap from about 54 to 179 ppm.
Three gallons, five gallons, or a rectangle
Three sources answer the tank question in three different units and none of them is wrong on its own terms.
- Aquarium Source: the recommended minimum tank size for chili rasboras is only 5 gallons. It is the one figure published as a minimum, and it is what this record carries.
- Aquarium Co-Op: we have successfully kept them in planted fish tanks as small as 3 gallons. That is a report rather than a recommendation, and the word planted is carrying the sentence.
- Seriously Fish: no volume at all, and a base measuring 45 by 30 cm, about 18 by 12 inches. That footprint is larger than either gallon figure implies, and it is the third record here where the specialist source measures the floor instead of the water.
Five gallons ties the smallest minimum in our fish silo, shared with the betta, the pea puffer and the african dwarf frog. The difference is what goes in it: this is the only one of the four that asks for eight to twelve animals in that volume.
Every source asks for the same tank around the number. Seriously Fish: best maintained in a densely-planted aquarium, with fairly dim lighting, and filtration that does not need to be particularly strong, because the fish may struggle if there is a fast current. Aquarium Source: at the bottom of the tank, use a dark substrate, either fine gravel or even sand.
And one instruction from Seriously Fish that belongs on this page rather than in a footnote: do not introduce any Boraras species to a biologically-immature aquarium. A three gallon tank that was set up last week is the failure mode the gallon figures invite.
The full record
| Field | Recorded | Where it comes from |
|---|---|---|
| Minimum tank | 5 gal | Three sources and three shapes of answer. Aquarium Source: the recommended minimum tank size for chili rasboras is only 5 gallons. Aquarium Co-Op reports its own practice rather than a recommendation: we have successfully kept them in planted fish tanks as small as 3 gallons. Seriously Fish gives no volume at all and asks for a base measuring 45 by 30 cm, about 18 by 12 inches, which is a bigger footprint than either gallon figure implies. The row prints 5 gallons because it is the only figure published as a minimum, and because the fish is kept in a school of eight to twelve rather than alone. Aquarium Co-Op's 3 gallon tanks were planted, which is the condition its sentence carries. |
| Temperature | 72 to 82 °F | Four bands, and 72 to 82 °F is the span every one of them contains. Aquarium Co-Op: temperatures between 72 to 82 °F, 22 to 28 C. Wikipedia gives the same. Seriously Fish is wider at 20 to 28 C, 68 to 82 °F, and Aquarium Source matches that and adds the only target figure anybody publishes: aim for 74 °F if possible. |
| pH | 6.0 to 7.0 | This is the sharpest split on the record and it is two against two. Seriously Fish gives 4.0 to 7.0 and Aquarium Source gives 4.0 to 7.0 with 6.0 as ideal. Aquarium Co-Op gives 6.0 to 8.0 from its own experience and Wikipedia gives 6.0 to 8.0. The two pairs overlap on 6.0 to 7.0 and that is what the row prints. What tips the reading is the wild water rather than a majority: Seriously Fish records the fish in black water streams stained brown with tannins, at a pH as low as 4.0, and asks for pH 5.0 to 6.5 to spawn it. Aquarium Co-Op reaches the same place from the tank: an acidic pH below 7.0 may help improve the hatch rate. Both halves of the disagreement point below neutral for breeding, and only one half will go below 6.0 for keeping. |
| Hardness | 54 to 179 ppm | Two sources publish a figure and they use different units, which this site has now hit on four records. Seriously Fish gives 1 to 10 dGH, general hardness, about 18 to 179 ppm. Aquarium Source gives 3 to 12 dKH, carbonate hardness, about 54 to 215 ppm. Taken as published the two overlap from 54 to 179 ppm, which is what the row carries. Aquarium Co-Op and Wikipedia both say only soft to hard water, which is the whole range. |
| Adult size | 0.7 to 0.8 in (18 to 20 mm) | Four figures and they agree, which is unusual on this record. Seriously Fish measures it properly at 20 mm standard length. Aquarium Co-Op: they only grow to about three quarters of an inch, 2 cm, long. Aquarium Source: the typical chili rasbora size is about 0.7 inches long. Wikipedia gives the range and the outlier: sizes range between 10 and 20 mm, 0.39 to 0.79 in, although the largest known specimen had a recorded total length of 3.1 cm, 1.2 in. It ties the ember tetra and the least killifish for the smallest fish on this site, all three topping out at 20 mm, though the ember tetra record and the male of the least killifish both start lower at 15 mm. |
| Diet | Micropredator, and it is easily out-competed | Wikipedia describes the wild diet: chili rasboras, like all members of its genus, are micro-predators with a diet primarily consisting of small insects, worms, crustaceans, and other zooplankton. Seriously Fish agrees with a hedge, that it is likely to be a micropredator feeding on small insects, worms, crustaceans and other zooplankton, and asks for daily meals of small live and frozen fare such as Daphnia and Artemia along with good quality flakes. Aquarium Source is the simplest: they do quite well on a balanced diet of fish flakes or small pellets. Aquarium Co-Op turns the whole field into a size problem, saying to look for fish foods that are small enough to fit in their mouths or are soft enough for them to take bites out of, and it names the risk that follows: they are not the most aggressive eaters and can easily be outcompeted. |
| Water column | Mid water | Every source describes a small schooling fish in the open water of a densely planted tank rather than at a surface or a floor. Seriously Fish asks for it to be best maintained in a densely-planted aquarium with fairly dim lighting, and it names the plants: Microsorum pteropus, Taxiphyllum barbieri or Cryptocoryne species. Two of those three are records on this site. On flow it is equally clear: filtration does not need to be particularly strong, and the fish may struggle if there is a fast current. |
| Lifespan | 4 to 8 years | Two sources publish a figure and neither is a care sheet from the two biggest names on this record. Aquarium Source: the average chili rasbora lifespan is somewhere between 4 and 8 years. Wikipedia: they can live up to 8 years if properly cared for. Seriously Fish and Aquarium Co-Op publish no lifespan at all. Eight years is a long time for a fish this small, and it is longer than our ember tetra, guppy or cherry shrimp records carry. |
| Growth rate | Not recorded yet | No source publishes a rate. What Aquarium Co-Op gives instead is a warning about what a young one looks like in a shop: juvenile chili rasboras are not very colorful at first, but with good care and patience, they will one day look as red as rubies. It also notes that they will temporarily become paler whenever they move from one tank to another, and to give them a couple of weeks to adjust. Neither is a growth figure and both are more useful than one. |
The same nine fields for every animal on this site are in the A to Z index.
Where our sources disagree
Every record here names a disagreement. On this one there are two, and the second is about the fish's character rather than its water.
Seriously Fish
Very peaceful but does not make an ideal community fish due to its small size and rather timid nature.
Aquarium Co-Op
In our experience, chili rasboras are refreshingly bold by comparison.
What we record: we print both and take neither, because they are not describing the same thing. Seriously Fish is comparing the fish to a community tank and concluding it does not belong in one; Aquarium Co-Op is comparing it to other nano fish and concluding it is the confident one.
Aquarium Source sits between them, calling it very peaceful and a bit timid at times. The practical difference is what you put it with. Seriously Fish names five genera of similarly tiny fish and pygmy Corydoras and stops; Aquarium Co-Op names lambchop rasboras, rosy loaches, ember tetras, dwarf cory catfish, neon green rasboras, snails and shrimp.
Both lists are small and slow, and neither contains anything that could eat it. The disagreement is about vocabulary, and the advice underneath it is identical.
The three plants it asks for, and we hold two of them
Seriously Fish names plants by scientific name rather than by shop label, which is rare enough to be worth quoting: Microsorum pteropus, Taxiphyllum barbieri or Cryptocoryne species.
Two of those three are records on this site. Microsorum pteropus is our java fern record and Taxiphyllum barbieri is our java moss record. Cryptocoryne is in the queue on our plants silo, named on two other records and still without a page.
The arithmetic works, which is not something this site can often say. Java fern runs 72 to 82 °F and this record runs 72 to 82: an exact match. Java moss runs 59 to 86 and contains it entirely. Both plants need no substrate, which suits the dark fine sand Aquarium Source asks for, and both are on the low light end that Seriously Fish's fairly dim lighting requires.
Aquarium Co-Op adds the plant to the breeding method rather than to the tank: cover the bottom of the tank with plastic craft mesh and put a thick layer of java moss underneath the mesh. The mesh lets the eggs fall through where the parents cannot reach them, which is the practical version of what Seriously Fish means by an egg-scattering, continuous spawner that exhibits zero parental care.
What can live with it, including shrimp
The temperament disagreement in station 04 produces two tank mate lists that look different and mean the same thing.
Seriously Fish concludes the fish does not make an ideal community fish and then names what it will accept: Microdevario, Sundadanio, Danionella, Eirmotus, Trigonostigma and pygmy Corydoras. Every one of those is a tiny, slow, mid-water or bottom fish. It adds that the species can be housed alongside freshwater shrimp of the genera Caridina and Neocaridina.
Aquarium Co-Op calls it refreshingly bold and names lambchop rasboras, rosy loaches, ember tetras, dwarf cory catfish, neon green rasboras, snails and shrimp. On the shrimp it is more precise than most sources manage: all fish will try to opportunistically snack on baby shrimp, but chili rasboras won't bother the adult shrimp.
Read the two lists together and the advice is identical. Nothing on either is fast, large, or capable of swallowing a three quarter inch fish. The two sources disagree about the adjective and agree about the animals.
Which of ours are on those lists
| Record | Named by | Its temperature | Against 72 to 82 °F |
|---|---|---|---|
| Cherry shrimp | Seriously Fish, as Neocaridina | 59 to 86 °F | Contains it entirely |
| Amano shrimp | Seriously Fish, as Caridina | 72 to 78 °F | Four degrees tighter at the top |
| Ember tetra | Aquarium Co-Op, by name | 72 to 82 °F | An exact match |
| Corydoras | Both, as dwarf or pygmy | 72 to 82 °F | An exact match |
| Nerite snail | Aquarium Co-Op, as snails | 72 to 79 °F | Three degrees tighter at the top |
Five of our records on two lists, and the water agrees with every one of them. The amano shrimp is the tight one, ending four degrees below this record's ceiling, which is the kind of thing our stocking calculator exists to catch before a heater setting does.
What do chili rasboras eat? Something small, and before the others get it
Two sources describe the wild diet and two describe the shopping. Wikipedia: chili rasboras, like all members of its genus, are micro-predators with a diet primarily consisting of small insects, worms, crustaceans, and other zooplankton. Seriously Fish hedges the same claim, that it is likely to be a micropredator, and asks for daily meals of small live and frozen fare such as Daphnia and Artemia along with good quality flakes.
Aquarium Source is the plainest: they do quite well on a balanced diet of fish flakes or small pellets. Aquarium Co-Op converts the whole question into one about size, and it is the most useful sentence on the subject: look for fish foods that are small enough to fit in their mouths or are soft enough for them to take bites out of.
Then it names the risk, and it is the reason the group size row matters: they are not the most aggressive eaters and can easily be outcompeted. Our ember tetra record carries the same finding about a fish of almost exactly the same size, and our otocinclus record carries it as easily out-competed in the temperament field itself. Three of the smallest animals on this site share one failure mode, and it is not the water.
Our brine shrimp guide exists for exactly this size of mouth: Artemia nauplii are what Seriously Fish asks for to raise the fry, after a week to ten days.
Male or female, and how to breed chili rasboras
Telling them apart
Seriously Fish: mature females are noticeably rounder-bellied and often a little larger than males, and males are generally more attractive with dominant individuals often displaying intense coloration. Wikipedia agrees and inverts the emphasis: the males are smaller than females and more brightly colored, with dominant males displaying the most vibrant coloration.
So the bright one is the male and the round one is the female, and both sources tie the color to dominance rather than to health. That matters next to Aquarium Co-Op's warning that juveniles are not very colorful at first and that a fish will temporarily become paler whenever it moves from one tank to another. A pale chili rasbora in a shop tank is not necessarily an unhealthy one, and a red one is not necessarily a well kept one.
Breeding
Seriously Fish describes an egg-scattering, continuous spawner that exhibits zero parental care, asks for spawning water at pH 5.0 to 6.5 and 1 to 5 degrees of hardness, and gives the timetable: it should begin to spawn the following morning, the eggs hatch by the second day after the initial spawning, the fry survive on their yolk sacs for another 24 hours, and after a week to ten days they should be large enough to accept Artemia nauplii.
Aquarium Co-Op gives the hardware instead: cover the bottom of the tank with plastic craft mesh and put a thick layer of java moss underneath the mesh, and it suggests an acidic pH below 7.0 may help improve the hatch rate. Aquarium Source confirms the pattern in one line, that these fish are continuous spawners whose eggs hatch in a couple of days.
Continuous spawner is the phrase to notice. Our breeding page is mostly about animals that need a trigger. This one lays eggs steadily and eats them steadily, so the mesh is not a convenience, it is the whole method.
What this record will not answer
Strawberry or phoenix rasbora against this one
It is the comparison people search for most after the care figures, and none of our four sources makes it. Aquarium Co-Op calls the chili rasbora a close cousin of other micro rasboras, like the exclamation point rasbora and strawberry rasbora, and describes none of them. Seriously Fish holds separate pages for the other Boraras species and this record does not borrow from pages it has not read as sources.
A growth rate
Blank, because nobody publishes one. What our sources give instead is better: a juvenile is pale and a moved fish goes paler for a couple of weeks.
Which pH to choose
The row prints 6.0 to 7.0 because that is what all four sources support. Below 6.0 you are following two of them against the other two, and above 7.0 the reverse. This record will not pretend that a four to eight range is a consensus.
Whether it is shy
Two sources say timid, one says refreshingly bold, and station 04 prints the quotes. What all three agree on is the tank mate list, which is the part that changes what you do.
How hard the water can be
Two sources, two units, dGH against dKH, and no conversion offered by either. The 54 to 179 ppm this record carries is the overlap of the figures as published, not a measurement anybody made.
Chili rasbora questions, answered from the record
What are the right chili rasbora water parameters?
72 to 82 °F, pH 6.0 to 7.0, and roughly 54 to 179 ppm hardness. The chili rasbora pH figure is the overlap of a genuine split: Seriously Fish and Aquarium Source give 4.0 to 7.0, while Aquarium Co-Op and Wikipedia give 6.0 to 8.0. In the wild, Seriously Fish records black water with a pH as low as 4.0.
What size tank do chili rasboras need?
Five gallons, which is the only figure published as a minimum. Aquarium Co-Op reports keeping them in planted tanks as small as 3 gallons, and Seriously Fish asks for a base of 45 by 30 cm instead of a volume, which is a larger footprint than either gallon figure implies. Whatever the volume, Seriously Fish says not to introduce any Boraras species to a biologically-immature aquarium.
How big is a chili rasbora school?
Eight to twelve. Seriously Fish: a schooling species by nature that really should be kept in a group of at least 8 to 10 specimens. Aquarium Co-Op: we like keeping a school of at least 8 to 12 together. The reason is in the feeding rather than the behavior: Aquarium Co-Op says they are not the most aggressive eaters and can easily be outcompeted.
What is the chili rasbora lifespan?
Four to eight years, from two sources. Aquarium Source: somewhere between 4 and 8 years. Wikipedia: up to 8 years if properly cared for. Neither Seriously Fish nor Aquarium Co-Op publishes a lifespan. Eight years is longer than our ember tetra, guppy or cherry shrimp records carry, on a fish under an inch long.
What do chili rasboras eat?
What to feed chili rasboras is a question about size rather than about type: small live, frozen and prepared foods. Wikipedia and Seriously Fish both file it as a micropredator taking small insects, worms, crustaceans and zooplankton, and Seriously Fish asks for daily Daphnia and Artemia with good flakes. Aquarium Co-Op gives the rule that matters: food small enough to fit in their mouths, or soft enough to take bites out of.
Are chili rasboras hardy?
Our sources do not use that word, and one of them says something more specific. Seriously Fish: do not introduce any Boraras species to a biologically-immature aquarium. A fish that needs a mature tank is not a fish for a first week, whatever else it tolerates. Aquarium Source calls the water range wide and Aquarium Co-Op reports keeping them in three gallons, so the tolerance is real once the tank is established.
Can chili rasboras live with shrimp?
A chili rasbora with shrimp is one of the few combinations our sources endorse without hedging, with one caveat that applies to any fish. Seriously Fish says the species can be housed alongside freshwater shrimp of the genera Caridina and Neocaridina, which covers our amano and cherry shrimp records. Aquarium Co-Op is more precise: all fish will try to opportunistically snack on baby shrimp, but chili rasboras won't bother the adult shrimp.
Chili rasbora or ember tetra?
Ember tetra vs chili rasbora is the comparison people search for most, and these are the two smallest fish on this site, tied at 20 mm, each named on the other's tank mate list by Aquarium Co-Op. Our ember tetra record carries 15 to 20 mm and pH 5.5 to 7.0; this record carries 18 to 20 mm and pH 6.0 to 7.0. Both want a densely planted tank with dim light, both are easily out-competed at feeding time, and both ask for a group. The honest answer is that this is a choice of color rather than of care.
How do I tell a male chili rasbora from a female?
The chili rasbora male vs female question is answered by shape and by color. Seriously Fish: mature females are noticeably rounder-bellied and often a little larger than males, while males are generally more attractive with dominant individuals often displaying intense coloration. Wikipedia says the males are smaller and more brightly colored, with dominant males the most vibrant. Both tie the color to dominance, so the brightest fish in the tank is the most dominant male rather than the healthiest fish.
How do you breed chili rasboras?
Stop the parents reaching the eggs. Seriously Fish describes an egg-scattering, continuous spawner with zero parental care, asks for pH 5.0 to 6.5 and 1 to 5 degrees of hardness, and gives the timeline: spawning the following morning, hatching by the second day, fry on their yolk sacs for another 24 hours, and Artemia nauplii after a week to ten days. Aquarium Co-Op gives the hardware: plastic craft mesh over the bottom with a thick layer of java moss underneath.
Why is my chili rasbora pale?
Two normal reasons, both from Aquarium Co-Op. Juvenile chili rasboras are not very colorful at first, but with good care and patience they will one day look as red as rubies. And they will temporarily become paler whenever they move from one tank to another, so give them a couple of weeks to adjust. Both sources that discuss color also tie the brightest color to dominance rather than to condition.
Is a chili rasbora a good community fish?
Our sources disagree about the phrasing and agree about the fish. Seriously Fish: very peaceful but does not make an ideal community fish due to its small size and rather timid nature. Aquarium Co-Op: in our experience, chili rasboras are refreshingly bold by comparison. Aquarium Source: very peaceful and can actually be a bit timid at times. Both tank mate lists contain only small, slow animals, so the practical answer is the same either way.
This is the only rasbora with a record here, and the name now has a guide. Our rasboras guide collects what four sources say about the group, and this record is the row on it that can be checked: the two published lists it compares give this fish pH 6 to 8 and pH 4 to 7, which is the same two against two split as the four sources in the table above, and they give it three to five gallons and ten gallons, a factor of three apart. On the group the two lists say 8 to 12 and 6 or more, and only the first of those reaches the 8 to 12 this record carries.
What a fish this small needs that a bigger one does not
Three things our sources ask for, and one of them is a filter that does less.
- A sponge filter, or anything gentleit may struggle if there is a fast current
- Dense planting and dim lightjava fern, java moss or cryptocoryne, named by species
- Food small enough to fit in its mouthand a mature tank, not a new one
Every item our records ask for is gathered on the tank setup topic.
Nothing here is a paid link. It is the shortfall between what this record asks for and what a boxed kit contains.
How this record was compiled
- By
- Verified
- Sources
Seriously Fish, Boraras brigittae, Aquarium Co-Op, chili rasbora care guide, Aquarium Source and Wikipedia, Boraras brigittae
- Conflicts
Printed above: two sources give pH 4.0 to 7.0 and two give 6.0 to 8.0, and the same sources split on whether the fish is timid or bold
- Blanks
Growth rate stay empty until a source we trust states them
- Not recorded
A growth rate, because nobody publishes one; and how this fish differs from the strawberry or phoenix rasbora, because the four sources on this record name those species without describing them, which is the comparison people search for most after the care figures