Chili rasboras are a tiny species of boraras that stay about .5″ (or 1 cm.) They’re colorful, peaceful, and active, which makes them a fantastic addition to tanks that need a pop of color and some movement.
They’re not difficult to take care of, but they’re not a good option for beginners or new tanks because they’re sensitive to changes in water quality. And they’re not the most ideal candidate for a hodge-podge community because of their small size.
They do, however, make planted nano tanks pop and give peace of mind to easily spooked South American dwarf cichlids, so if that sounds like a fish you want, read on!
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Table of contents
Table of Contents
FAQ
Can I keep chili rasboras with shrimp or bettas
Chili rasboras do great with shrimp! Particularly because the smaller, non-predatory species of shrimp won’t eat them, and they’re unlikely to eat shrimplets. With bettas, it’s a little bit more difficult. I wouldn’t keep them with splendens, but smaller betta species would work.
I included my betta species suggestions in the tankmate section.
How many chili rasboras per gallon?
These guys shouldn’t be kept in anything less than a 5-gallon in numbers less than 6. But you can get away with two chili rasboras per gallon. Like shrimp, they’re so small that they really don’t have a bioload (so you can do more per gallon, and I personally would, but two is what I suggest for most people.)
Are chili rasboras hardy?
Chili rasboras are pretty hardy once they’re established in a well-established tank. They don’t do well in new tanks, and they don’t handle environmental changes super well. So… kinda?
Chili Rasbora Classification
IUCN Status: Not listed
Class: Actinopterygii are ray-finned fishes, which is a subcategory of boney fishes. These fish are characterized by the bony structures that support their webbed fins. This group makes up nearly half of all living vertebrates.
Order: Characiformes are a subgroup of ray-finned fishes including characins and 17 other recognized families.
Family: Characidae is a family belonging to characiformes that hail from tropical and subtropical waters. Although there is some scientific debate surrounding the preferred name for this family, “characids” is preferred by scientists.
Genus: Boraras is a genus of cyrinids from Asia, which includes six recognized rasbora species.
Species: Boraras brigittae
What does Boraras brigittae mean?
Boraras is an anagram of the generic name Rasbora. This is a nod to the reversed ratio of abdominal and caudal vertebrae in this genus. Though, admittedly, kinda a meta nod.
Though it’s worth noting that boraras is also cited as being used as a part of what Borneo natives call some fish (boraras merah.)
Brigittae is named for the discoverer’s wife.
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Distribution & Natural Habitat
Chili rasboras, as far as we know, are endemic to southwestern Borneo. They inhabit blackwater streams and pools and can be found in some peat swamps, where the pH can be as low as 4.0.
In almost all instances, the dKH is incredibly low – or nonexistent and there’s dimmed lighting from surrounding plants. Though this species hasn’t been covered by the IUCN, there’s a real threat to their natural habitats being destroyed – particularly ancient peat swamps.
Aquarium Care
Difficulty: Easy – food can be tough
Size: .5″ (1 cm)
Lifespan: 6 – 8 years
Tank Size: 5+ gallons (20+ liters)
Diet: Omnivore – will take pellets
Temperature: 68 – 83F (20 – 28C)
Tank Specs
You can keep chili rasboras in a small shoal of six (maybe a few more) in a mature five-gallon tank. Stability in water chemistry is super important for these guys, so you’ll need to make sure your filter is set up to handle the – albeit light – bioload. Once parameters start fluctuating, you’ll lose chili rasboras relatively quickly.
You’ll also want a lid and a way to dim the light coming into the tank. These aren’t your usual jumpers, but nonetheless, they can, do, and likely will jump. Floating plants lessen the risk as well as help blot out some light, and I’ve included some in the plant section.
Even though these guys can go down to 68 F, you’ll want a heater to keep it in the high ’70s and to make sure their temperature stays stable. If their temperature swings drastically, you’ll likely experience issues with illnesses or deaths in your shoal.
If you don’t know where to start with heaters, I have a whole article about the best heaters on the market (or you can see the top one below.)
Stocking
Chilis do best in shoals of six or more, with a heavy emphasis on “more.” Ideally, you’ll want to get at least a dozen to start your shoal. If you can get two or three females for every male, that makes it all the better.
When spawning, dominant males form small territories and can get into minor squabbles over territories with rival and subordinate males. So the more males you have, the larger you’re going to want your tank to be so they can each set up their own space – or at least avoid other males if they’re not dominant enough to set up their own chunk of land.
Decor
Chili rasboras do best in a densely planted setup with some space to swim. Since they’re small, they don’t need massive amounts of open space in the tank, but a spot in the front and center would be a good choice.
Leaf litter and other botanicals would make a great addition to the tank. Not just because of the natural feel and addition of tannins to the water, but also as a secondary food source of tiny microorganisms for them as well as any fry that may appear. Tannin Aquatics is, of course, my favorite (I know, I know, I’ve totally never mentioned them before or anything… 🙄)
For this setup, anything can go, really. But if you’re looking for some cool finds, they have banana stems and palm flowers that would make a neat addition to the usual dried leaf litter selection they have.
The addition of driftwood, root structures, or a blackwater additive like Brightwell Blackwater would also be appreciated by these guys.
As far as substrate goes, my no-fail (and also totally never mentioned before) suggestion of HTH pool filter sand should work. HTH sand is super cheap, but I recommend you buy it in person because it’s not worth the online markup for shipping. I only linked it so you can see if it’s in a store near you. I have heard of people using Play Sand as well, but I find it gets too compact for me.
If you want some high-maintenance plants you sand just isn’t going to cut it for you, the best plant substrates are listed below as well.
Best Plants For Chili Rasboras
There’s not a ton of plants that chilis wouldn’t do well with. Some things to look for are thick or bushy plants that can handle lower levels of light and softer water. You can, of course, opt for some thinner, slower-growing plants, but you’re either going to need to spend more upfront to fill your tank in or your chilis are going to be uncomfortable while they wait for the plants to bulk up.
The final thing to consider that I, unfortunately, can’t help you with is your skill level. Below is a list of the easiest plants that would do well in a chili rasbora tank, but your options open up if you have the time and skill for more advanced plants.
Bacopa sp.
Bacopa comes in a variety of species and variants – some more demanding than others – but the least demanding is Bacopa carolinia. It is banned in a few states because of its invasive species status, but it makes a wonderful addition to most aquariums if you can get it.
Vallisneria
Vals come in a ton of varieties, but most of them are about the same to grow. They can grow rapidly, and quickly cover your tank with lush, kelp-like forests for your fish. Some species, however, do grow much shorter than others.
Java Moss
Java Fern
Java fern is a nearly indestructible low light plant that can put up with tons of abuse. It doesn’t need Co2, fertilizers, or fancy soils. There are tons of lush, beautiful, jungle-like aquascapes you can create with it too!
Guppy Grass
Guppy grass is a great floating plant that adds depth, structure, and cover to any tank. It’s a super easy plant to grow and takes up tons of ammonia, nitrates, and nitrites, but – beware – it grows fast and can easily overrun your tank. Overall, it’s an amazing plant to have if water quality is your top concern.
Guppy Grass
Guppy grass is a great floating plant that adds depth, structure, and cover to any tank. It’s a super easy plant to grow and takes up tons of ammonia, nitrates, and nitrites, but – beware – it grows fast and can easily overrun your tank. Overall, it’s an amazing plant to have if water quality is your top concern.
Salvinia
Salvinia is a fast-growing plant good for keeping ammonia, nitrates, and nitrites under control. It’s great for providing shelter for scared fish and fry, keeping the lighting intensity down. and making skittish fish feel more secure.
Duckweed
Duckweed can be a blessing or a curse. It’s a small floating plant that’s impossible to kill and can quickly and cheaply cover the top of your tank. The tough part is that it’s nearly impossible to fully get rid of once it’s in your tank.
Lighting & Filtration
Chili rasboras prefer dimmed lighting. You can achieve this in a few ways – the easiest being floating plants. If you’re looking for a bit more control over the lighting going into your tank, there are some good customizable lights on the market that are plug-and-play, and I’ve included some of those below for you.
As for filtration, these little guys can easily struggle against most levels of current, so you’ll want your sponge filter to be fairly low. Enough to create a little bit of surface agitation and water movement is sufficient. If you don’t know where to start with sponge filters and air pumps, I’ve listed the best of those below for you as well.
Water Care
Stability is the most important thing when it comes to keeping chili rasboras, so the more small water changes you can do, the better. Of course, how much water you change at any given time totally depends on your water conditions in the tank as well as out of tap.
Aim for somewhere in the 10% twice a week or 15% weekly range to keep things super stable for them. If your tank and your tap aren’t close to each other, aim for even smaller, more frequent water changes. Of course, you’ll need a quality tap water conditioner (or dechlorinator) and a little bit of aquarium salt never hurts, either.
With these guys, it’s not as much about removing waste as it is about keeping the chemistry in their tank stable. If it swings too much or too rapidly, you’re likely to see die-offs, or at least an outbreak of disease.
Speaking of diseases, everything you’ll need to treat common chili rasbora diseases is listed below.
Feeding Chili Rasboras
Feeding chili rasboras isn’t hard if you find food that they can fit in their mouth, which can be a little challenging if you’re not used to tiny fish. Some good options for live food are baby brine shrimp, small daphnia, microworms, vinegar eels, wingless fruit flies, small bloodworms, mosquito larvae, and anything you would generally feed to small fry.
Frozen food is a little bit tougher since most of the options are a bit large. You can try chopping bloodworms into smaller pieces or looking for frozen baby brine.
Dried foods are considerably easier to find in the right size or crumble up, but they’re not as nutritious as the other options. Some of the best dried options are golden pearls, decap brine shrimp eggs, crushed freeze-dried daphnia, and other small foods in the 100- to 150-micron range will be gladly accepted by small fry, anything under 500 should be easily accepted by small adults, and anything under 800 should be accepted by full-grown adults.
Even larger fish will eat smaller-sized foods. I would avoid flakes because they don’t retain a ton of nutrients and they’d be hard to break down to those sizes. If you’re having a hard time find the right sizes, I have some favorites listed below.
Common Chili Rasbora Diseases
Chili rasboras are pretty hardy if you put them in a mature tank and keep them stable. If water parameters fall out of whack or if they’re brand new fish, here are the most common illnesses you can expect to see in them:
Fungal Infection
Fungal infections are a tricky bunch – not only do they have a huge family that presents a wide variety of species and symptoms – but some bacterial infections look strikingly similar to a fungus.
If you’re not sure if you’re dealing with a fungus or a bacterial infection, I find it helpful to treat with Ich X and Erythromycin (provided it’s 100% erythromycin) at the same time to be sure I’m treating for both.
Symptoms:
- Cottony growths on body, fins, eyes, and/or gills
Causes:
- Prior untreated injury
- Stress
- Water quality-related issues
- Prior untreated infection (bacterial, parasitic, etc.)
Bacterial Infection
Bacterial infection is a broad term, the bacteria family can cause a wide range of symptoms and come from varying causes. Generally, you can treat them with a broad spectrum antibacterial regardless of the particular bacteria at hand. It’s diagnosing that’s usually the hard part.
Making matters even more difficult, fish can have an internal or external bacterial infection.
Symptoms:
- Red streaks
- Red ulcers
- Fuzzy growths
- Pop eye
- Bloating
Causes:
- Poor water quality
- Food that’s gone bad
- Keeping fish in inappropriate water parameters
- Stress
Columnaris (Cotton Mouth Disease)
Occasionally called false neon tetra disease or cottonmouth, this is caused by a gram-negative bacterium. it can also, quite understandable, be confused with fungal infections.
Symptoms:
- Discolored scales
- Scales appear to be popping off (not “pineconing”)
- Grey spots
- Lesions on the back
- Legions around the mouth
- May result in fuzzy patches due to secondary infections
Causes:
- Flavbacterium columnare (bacteria)
Ich (White Spot Disease)
Ich is caused by a parasite that, to many, looks like tiny white pimples across the fish. It can attach to the mouth, fins, body, and gills. You can usually see fish scraping themselves against objects (likely because parasites are itchy!) before white spots even appear.
Symptoms:
- White spots
- Scratching
- Redness or bloody streaks
Causes:
- Ichthyophthirius multifilis (parasite)
Chili Rasbora Tank Mates
Chili rasboras do well with other small, peaceful fish. Particularly other small cyprinids (rasboras, minnows, tetras, etc.) as well as dwarf cichlids, small anabantoid species (gouramis and betta), and small catfish.
Anything that’s not going to eat it, enjoys softer, acidic water, and doesn’t like a ton of water movement is a good match. Here’s a small list of potential tankmates. It’s not a complete list by any means, but I hope it will give you some ideas to start with!
Cherry Shrimp (Neocaridina davidi)
Neos enjoy munching on decomposing plant matter, grazing on algae, and picking sunken pieces of wood and plants clean. This makes them a perfect addition to a naturalistic tank. They come in a variety of colors including the oh-so-common cherry shrimp!
pH: 6.5 – 8.0
dKH: 8 – 20
Temp: 70 – 79 F (21 – 26 C)
Size: 1.6″ (4 cm)
Temperament: Peaceful
Swimming: Anywhere there’s food to pick, but usually bottom
Crystal Red Shrimp (Caridina cantonensis)
Crystal red shrimp, not unlike cherry shrimp, come in more colors than just red. They’re a similar size to cherry shrimp and make a great alternative if you’re looking for a little bit more of a challenge. They’re incredibly popular – although more expensive.
pH: 5.8 – 7.4
dKH: 0 – 4
Temp: 62 – 76F (16 – 24C)
Size: 1.25″ (3 cm)
Temperament: Peaceful
Swimming: Surfaces
Pencilfish (Nannostomus sp.)
Pencilfish is a genus containing 19 currently recognized species. Some popular options are diptails, Beckford’s, and coral. Although it’s a large genus, the care is similar for all of them and you should aim for a shoal of at least six.
Research into a specific species and their requirements is strongly recommended.
pH: 5.0 – 7.0
dKH: 4 – 12
Temp: 74 – 82F (23 – 27C)
Size: 2″ (5 cm) species dependent
Temperament: Peaceful
Swimming: Mid to top
Ember Tetra (Hyphessobrycon amandae)
Ember tetras are bright, fun, tiny, shoaling fish that occur in South American black waters. They’re hardy, peaceful fish that are often described as active, bold, and playful. They also enjoy a planted tank, but be mindful that they do like to swim in open space, so be sure to include that in your layout. They enjoy their numbers a little higher than most shoaling species, 8 is recommended.
pH: 5.5 – 7
dKH: 1 – 10
Temp: 68 – 82 F (20 – 27 C)
Size: 3/4″ (2 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling
Pygmy Corydoras (Corydoras Pygmaeus)
The pygmy cory (corydoras pygmaeus) is the smallest of all the corydoras species and – possibly – the smallest catfish in the world. It’s a peaceful shoaler that appreciates sandbeds and at least six of their own kind.
pH: 6.2 – 7.4
dKH: 2 – 15
Temp: 60– 78F (15 – 25C)
Size: 1.3″ (3.5 cm) max
Temperament: Peaceful shoaling fish
Swimming: Everywhere
Toucan Tetras (Tucanoichthys tucano)
These guys are hard to find (but I know a few good spots if you want them!) And they’re completely worth hunting down these rare gems. They’re a peaceful shoaling fish that need to be kept in groups of six or more and the only known wild population exists within a 200-meter range in Brazil.
pH: 4.0 – 6.5
dKH: 1 – 8
Temp: 68 – 83F (20 – 28C)
Size: 1″ (2 cm)
Temperament: Peaceful shoaling fish
Swimming: Mid to top
Bolivian Ram (Mikrogeophagus altispinosus)
The underrated cousin to the German Blue Ram are often nearly colorless and shy in the store tanks. But provided with the right tank and dither fish, they’ll color up and exhibit fascinating behavior in your home aquarium!
Keep in mind these rams will also become territorial while spawning. However, there are some sparse reports of other tankmates going unnoticed during spawning.
pH: 6.0 – 7.5
dKH: 1 – 10
Temp: 68 – 83 F (20 – 28 C)
Size: 3″ (8 cm)
Temperament: Peaceful
Swimming: Bottom to mid-water
Parosphromenus harveyi (Licorice gourami sp.)
Parosphromenus harveyi are difficult to find and tricky to care for, but they make a beautiful addition to a well-planned tank. They’re endangered, so special care should be taken to ensure they’ll thrive.
pH: 3.0 – 6.5
dKH: 1 – 4
Temp: 72 – 83 F (22 – 28 C)
Size: 1.3″ (3 cm)
Temperament: Peaceful and shy
Swimming: Mid to bottom
Chocolate Gourami (Sphaerichthys osphromenoides)
Chocolate gouramis are slightly tricky to keep and need to be kept in groups of six or more. They’re peaceful, shy fish that need soft, acidic water to survive and generally don’t accept prepared foods well.
pH: 4.0 – 6.5
dKH: 0 – 3
Temp: 74 – 86 F (24 – 30 C)
Size: 2″ (5 cm)
Temperament: Peaceful and shy
Swimming: Mid to bottom
Samurai Gourami (Sphaerichthys vaillanti)
An endangered and slightly tricky to keep species, the samurai gourami makes a beautiful addition to most well-planned soft water tanks. They need to be kept in groups of 6 or more and usually don’t accept prepared foods.
pH: 3.5 – 6.5
dKH: 0 – 3
Temp: 70 – 77 F (21 – 25 C)
Size: 2″ (5 cm)
Temperament: Peaceful and shy
Swimming: Mid to bottom
Betta miniopinna (Coccina complex)
Betta miniopinna is critically endangered, which means it’s one small step away from being extinct in the wild. They’re tough fish to keep for water chemistry reasons, but feeding them and keeping them once they’re settled is pretty easy if you have experience with touchy water chemistry.
pH: 4.0 – 6.0
dKH: 1 – 5
Temp: 72 – 83 F (22 – 28 C)
Size: 1.3″ (4 cm)
Temperament: Peaceful and shy
Swimming: Everywhere
Betta persephone (Coccina complex)
Betta persephone are an endangered species of betta. These are a smaller and more peaceful species of betta, but their care requirements are much trickier – particularly with their water chemistry, so experience is required.
pH: 4.0 – 6.0
dKH: 1 – 5
Temp: 72 – 83 F (22 – 28 C)
Size: 1.3″ (4 cm)
Temperament: Peaceful and shy
Swimming: Everywhere
Rosy Loach (Petruichthys sp. ‘rosy’)
Rosy loaches are best kept in groups of at least 6 and they do best in planted setups. They’re often wild-caught, so most of them are in poor condition when you buy them. They also need to be added to a mature aquarium since they don’t do well with environmental swings.
pH: 6.5 – 8.5
dKH: 5 – 15
Temp: 68 – 79 F (20 – 26 C)
Size: 1.2″ (3 cm) max
Temperament: Peaceful and active
Swimming: Mid to bottom
Breeding Chili Rasboras
Once chili rasboras start spawning, they spawn pretty much constantly and will eat their eggs or fry if given the chance. Fortunately, they don’t hunt down their eggs or fry like most fish will, so there’s a decent chance that you will see some fry start to pop out if there’s enough cover and micro-food in the tank.
To start, you’ll want a few dominant males and at least 1 – 2 females per male in your tank. Unfortunately, due to the color variations based on dominance, condition, gender, and even just within the species, they’re impossible to sex by color or intensity alone. The big determining factor between males and females will be the more rounded or bulkier body shape in well-conditioned, mature females combined with the color differences.
For the best chances of getting fry, you’ll want to set up a separate breeding tank. You can, of course, try your luck in the main tank if it’s well-planted.
Spawning
Spawning chili rasboras is similar to most small cyprinids. You’ll want to add small groups to spawning containers with marbles, plastic grass, or a mesh at the bottom large enough for the eggs to fall through, but not large enough for adults to get through. The containers can be as small as a 2-gallon, but shouldn’t be larger than a 5-gallon for ease of feeding the small fry when they hatch.
From there, if the fish are well-conditioned, they should spawn continuously while they’re in there. Their spawning activity, for the most part, looks like rambunctious chasing. You can leave them in there for three to four days, anything after that and you run the risk of fry potentially being eaten when they start free-swimming.
Here’s a good video if you want more information on the setup and process.
In such small spaces, you’re probably not going to be able to fit much in the way of filtration but, if you can, a small sponge filter is a great option. If you can’t, a handful of fast-growing plants is a good option to help keep the water clean as well as offer the fry their first micro foods such as infusoria.
Egg & Fry Care
Successfully breeding chili rasboras is easy, raising the fry to maturity is a feat for most.
Depending on the water temperature, the eggs will hatch anywhere from 36 to 72 hours, and they’ll become free-swimming anywhere from 36 – 48 hours after that. When they first hatch, they’re insanely small and will need to be fed infusoria-sized foods.
Live food will be your best option if you can culture infusoria and keep enough going to get them through the critical first few weeks. If you can’t, you can try using Hikari First Bites or Repashy’s Spawn & Grow (just the powder) but the powders will likely be too large for them, will quickly pollute the tank, and they probably won’t have much interest in non-moving food anyway.
Because of their small size and even smaller food size, it’s best to move them to a smaller container if your breeding container wasn’t small enough so they can easily find enough food. A two-gallon would be a good start for a large brood, but a one-gallon would suffice with good hygiene practices.
Within two weeks they should be able to take larger foods like microworms, vinegar eels, and possibly baby brine depending on how quickly they’re growing. At this time, it would be a good idea to move them to a larger tank to keep the water parameters stable. By three months they should be large enough to move into the main tank with the rest of your adults. By six to eight months they should be mature enough to breed themselves.
Further Reading & Resources
Science Mag – Tropical Peat Forests in Trouble