Chili Rasbora Care Guide: Bororas brigittae

Packed with color and personality, the chili rasbora, or Bororas brigittae is one of the most gorgeous little fish you could get for your aquarium. They do really well in planted tanks and don’t need much space. On top of that, they’re pretty hardy as long as you meet a couple simple housing demands. Keep reading or check out the video below to learn everything there is to know about keeping chilis!

Appearance and sexual dimorphism

Chili rasboras, or Boraras brigittae are a truly dainty little fish, maxing out at about ¾ of an inch or 2 cm. Don’t let that little size fool you though, they are packed with color. Their bodies are intensely dark red, a crimson or scarlet, with a black line running down their bodies from their head, tapering off to their tail. Red coloration is especially pronounced around the black dash, forming a bold red outline. Fins are dotted with more subtle crimson specks that appear as fins open up.

One of the things that I enjoy most about chili rasboras is how their colors change depending on the angle that you look at them from. Obviously the bold red colors are incredible, but there are so many subtle colors that pop from different angles. When you look down on them from the top, they have that white to silver shimmer.

Their bodies do an amazing job of reflecting light, which can show up as almost yellow or green hues of light. My absolute favorite subtlety of the chili rasbora is the white spot that flashes at the very end of their body, bordering the tail; it’s really hard to catch a glimpse of.

When you first buy young chili rasboras, they won't be so brightly colored. It can take up to a year for them to reach maturity and full coloration. Dominant males will exhibit a bolder red color than subdominant males or females, though they can still look extremely pretty. Females are slightly larger and rounder than males. 

Chili rasboras are pretty moody little fish. You can tell by their color. If I go away for a few days and they don’t eat during that period, they’ll become quite pale, and then color up almost immediately after feeding. They also seem to really enjoy water changes, picking up lots of color after filling the tank. 

Chili rasboras are not easy to get good pictures of! At least for me…

Origin

Chili rasboras are native to swamps of Southern Borneo and Indonesia. These peat laden swamps are surrounded by jungles. Water flows very slowly through the dark murky swamps. Large trees hang over the water casting shade over the swamps and dropping leaves in. These are called blackwater habitats, because of the high levels of tannins that are introduced via peat moss and fallen leaves.

Tank specs

It’s not that hard to set up a tank for chilis. They really don’t need tons of space - I have mine in a 9 gallon or 34 liter tank. You could probably give them less space, but this is kind of my personal minimum size tank for any fish. You get a lot better coloration and opportunity to observe natural behaviors when you give them a little more space.

They do really well in blackwater aquariums, but also thrive in typical planted aquariums. Packing the tank with lots of plants is a great way to give them ample hiding space as well as biofilm to feed on. A dense jungle of plants is important to help reduce light entering the tank; these fish will color up most brightly in lower light settings. 

Light colored sand is not always recommended for the best coloration, but as you can see here, even with light sand my chilis are fairly well colored.

Even though lots of guides will say that biofilm on leaves is important for them, I rarely see mine nibble on that. They will on occasion hide in leaf litter when I startle them during maintenance sessions.

The absolute most important factor for their tank, is not to blast them with flow. They are such dainty little fish that aren't able to tolerate much flow. If they end up getting sloshed around the tank, it will be hard for them to live healthy lives. They’ll exert a ton of energy to just stay afloat. Feeding will also be difficult, further exacerbating their little bodies. This is one of the biggest factors that I don’t see people meeting for their chili rasboras. 

In this tank, I have a flow reducer on the output to keep turbulence down while not reducing the filtration.

Water parameters

Chili rasboras can tolerate a wide range of conditions. The swamps that they come from tend to experience wide shifts in pH, as low as 4 on top of big temperature changes. It’s not something you’d want to aim for in your tank, but fortunately does provide us with some leeway in caring for them.

Temp - 70℉ - 82℉ or 21℃ - 27℃

pH - They do prefer water to be slightly acidic, shoot for 6 - 7. They can live healthy lives in a pH of up to 8 and can even live in water with pH as low as 4 for brief periods.

GH & KH - 2 - 10

Ammonia 0
Nitrite 0
Nitrate under 20/30

Behavior

These little guys spend most of their time poking around the tank. They tend to have kind of jolty movements, where they’ll hang out in one spot for a while then bounce off to another location for a bit. Being a social fish, they feel most comfortable in the company of each other; it’s a good idea to keep a school of at least 10 of them. I have 18 in my 9 gal.

Dominant males will carve out little territories, chase away other males and court females, hopefully attracting them to their little areas.

Although I’ve often seen them described as timid, that is certainly not what I’ve observed. They know that my hands are the ones that feed them and as soon as they see me enter the room they are all at the front, top of the tank waiting for a meal. Part of their confident nature is that I’ve done a good job in providing them with plenty of hiding spots, low current and no aggressive tank mates. Make sure to check all the boxes in order to encourage outgoing behavior.

Diet

Chili rasboras are not picky eaters. They are mostly carnivorous in the wild, but it’s not a bad idea to introduce a variety of foods in the aquarium. The absolute MOST important thing to consider is that they have extremely tiny mouths. These little mouths can only eat what fits into them. They don’t have shark teeth or cutlery to rip off edible pieces of food from larger chunks. You’ll need to either find small bits of food, or crumble them yourself. 

I like a stiff flake like Omega One that crumbles really well between your fingers. You can also take the flake residue from the lid or side of the jar and sprinkle that in. Live foods are really appreciated by chili rasboras. Some of my go to’s are grindal worms, freshly hatched brine shrimp and wingless fruit flies. 

I can’t stress enough how important it is to feed them small sized foods. You can feed them once a day, but they certainly would benefit from twice daily feeding due to the fact that they have such small stomachs and can't fit much in there in one sitting.

Live grindal worms are a terrific source of protein for chilis, and they’re easy to culture at home!

Tank mates

Similar sized fish with calm demeanors make for good tank makes with chili rasboras. Fish like cory cats or kuhli loaches that are peaceful and inhabit different parts of the tank are perfect. Shrimp also make for good tank mates. I keep blue bolts or Caradinas in with my chilis and they breed just fine. I’ve read that chilis can eat baby shrimp, but I’ve never seen it and I’m not convinced that they are able to do that, given the small size of their mouths.

A lot of people mix them with peaceful schooling fish like larger rasboras and tetras, which makes feeding difficult from a competition standpoint. It’s not that they will bully the chilis, they’ll just outcompete them during feeding time. If you do keep mixed groups of fishes, make sure to watch as you feed and guarantee that all your chilis are getting a good meal.

Obviously it would be a mistake to place them with larger fishes like angels or African cichlids. They’d get chomped instantly!

Breeding

Chili rasboras are not the easiest fish to successfully breed due to their small size. Newly hatched fry are almost impossible to detect and are susceptible to being eaten by everything and anyone in your fish tank, as well as being sucked into filters.

Females will scatter eggs over well vegetated areas. Males will follow up by fertilizing eggs. Probably the easiest and highest likelihood of success in breeding could be achieved by lining a larger tank in moss and only keeping a small number of well fed adult chili rasboras. It will need to be a mature aquarium with lots of microscopic plankton. Adult chilis will prey on juveniles, so keeping a small number in a large tank with tons of fine hiding spots will really optimize the chances of fry survival.

Similar species

OK, last thing to mention are that there are a few species that very closely resemble chili rasboras. I’ve read accounts of them being accidentally sold as chilis, because juveniles are difficult to distinguish from each other. Some species that could easily be confused for chilis especially at young ages are phoenix rasboras, exclamation point rasboras, dwarf rasboras and strawberry rasboras.

There’s also potential from them to crossbreed, resulting in hybrid offspring. I’ve read about this, but I can’t verify the accuracy of this statement. In the wild, it’s not common for species to cross breed because it’s not geographically (and/or biologically) possible. It’s also easy to get confused due to the fact that their colors can change so quickly and that females can sometimes be a lot blander color. 

That’s it for chili rasboras; drop a comment if you have any questions! 💬