Scarlet Badis Care Guide: Tank Mates, Feeding & Breeding

The tiny, agile, and beautiful Scarlet Badis has begun to establish itself well in the hobbyist nano aquarium arena. They’re tiny, but they pack a big visual impact. Their gem-like patterns and unique niche are a huge draw, but you shouldn’t bring any fish home until you know it well.

That’s what we’re here for! Let’s dive right in, and we’ll help you learn all the facets of Scarlet Badis care.

scarlet badis


Scarlet Badis Quick Care Sheet

Common Name: Scarlet Badis

Alternate Common Name(s): Gem Badis, Scarlet Dario, Dario Fish

Latin Name: Dario dario

Care Level: Intermediate

Tank Size: 10+ gallons

Size: Males ¾”, Females ½”

Diet: Carnivorous

Behavior: Semi-aggressive, males aggressive with other males

Lifespan: 3-4 years

Reproduction Type: Egg Layer

Water Temperature: 70°-78°F(21°-26°C)

pH: 6.5-8.0

Water Hardness: 10-20dGH

Introducing the Scarlet Badis

The Scarlet Badis has quickly become a favorite for those who keep nano tanks due to their small size and lively behavior. The males reach up to 1” in length, but most tend to be around the ¾” spot while the females reach around ½” when fully grown.

Sometimes confused for cichlids, they’re more closely related to Gourami. That said, they lack the distinctive labyrinth organ that defines Anabantoids. Instead, they breathe through just the usual gills.

While lively, these fish are a little understudied compared to many in the trade. Nano-tanks have become more popular in recent years, however, and led to a surge of interest in smaller fish to populate them.

Scarlet Badis, as fish in the home aquaria, prefer a calm environment with a lot of plants. Their tanks should have a bit of length to them, and if you’re running a nano-tank that means you should find a tank that isn’t a cube to place them in.

While they’re a bit feisty, Scarlet Badis are too small to do much damage to plants. Their behavior can be similar to a cichlid but they won’t be able to trash a planted tank in the same manner, if at all.

These fish tend to be a bit timid, Scarlet Badis do well in the right community tank but do best when they’re in a species-only enclosure created specifically for them.

Keeping them happy brings out their bright colors even more, and it’s a good way to judge their health.

The Scarlet Badis is a well-adapted micro predator, swift and dangerous to anything that will fit in its mouth. Fortunately for us and our tanks, individual microfauna are rarely of any interest to the aquarist. 

That does mean you’ll want to feed your Scarlet Badis meaty foods but there’s a catch.

In some cases, juvenile Scarlet Badis won’t eat food that’s not alive. That’s not a huge problem since it’s easy to breed many types of prey for freshwater fauna, but it requires more expertise than most common aquaria fish call for.

Your Dario dario is also rather sensitive to water quality. This isn’t a fish you’ll want to cycle a tank with, but they’re pretty good at adapting to temperature swings. Make sure that you know what your local water is like. If you’re buying them in person, ask your LFS if they’ve had to make any adjustments to the water for the best results.

The Scarlet Badis is a beautiful, active fish that requires a little more care than something like a Neon Tetra. For those willing to put in the work, raising them is a rewarding experience that can help a new aquarist expand their skill set.

Origins of the Scarlet Badis

When we talk about fish care, one thing that often gets glossed over is their natural environment. Some fish have been bred in tanks for decades, but Scarlet Badis are new-ish to the trade.

That means learning how to mimic their natural environment is the best way to care for them.

Dario dario, as a wild species, exists in a few specific tributary systems in India. There they live in waters around 3’ deep and spend their lives among dense vegetation. That means in the wild these fish are in shallow water with high flow volume.

Many Scarlet Badis are wild-caught. Wild-caught fish may not accept dead food, in which case you’ll have to feed them live food. Daphnia, cyclops, and brine shrimp are all easy to breed at home to create a constant food source for your fish.

A fish’s origin is important to understand, especially for fish that don’t have decades of history of being captive bred. It’s the first place to find hints leading to the best care possible for your fish.

The big takeaways about the natural habitat of these fish are simple:

  • Clean, flowing, and shallow water
  • Heavy vegetation
  • Large areas

Ideal Tank Setup

The ideal Scarlet Badis tank is going to loosely mimic their natural environment.

The following should all be given thought:

  • Fully Cycled Tank- First things first: Scarlet Badis are very susceptible to water pollutants. Cycling with these fish in is asking for a disaster, so make sure that the tank is fully cycled with low nitrates(preferably <10ppm) before you add any Dario dario to the tank.
  • Mild to Moderate Flow- Avoid over-filtering your tank and adding too high of a flow volume. While they don’t need gentle water, you’re not trying to create a rushing river either. 4x tank volume per hour is a good start, if you need more filtration then you may want to use sponge filters as a supplement.
  • Heavily Planted- The waters that these beautiful little fish come from are teeming with life, and flora is a large part of it. A few of the species in the area are available, but a focus on Rotala sp., Cryptocoryne sp., and Java Moss is a great way to start.
  • Cave Structure- Scarlet Badis’ have developed a reputation for being shy when bigger fish are present. Plants provide a substantial amount of cover, but to truly make these fish feel secure they need a small cave. You can create one with any hardscape element like driftwood or rocks.
  • Soft Substrate- You don’t necessarily have to go with sand, but you’ll need something a bit softer than the usual gravel. These little fish spend a lot of time on the bottom of the tank and their natural environment has a sandy bottom with small pieces of gravel.
  • Adequate Space- Despite their small size, Scarlet Badis need a good bit of room. A standard 10-gallon tank is good for a single male and two or three females. Do not add multiple males to a 10-gallon tank, and add them cautiously in larger tanks.

It’s actually an easy order, the Scarlet Badis comes from an environment that’s easy to replicate in aquaria. The biggest mistake people make in care is not letting the tank cycle first

People often tend to set up nano-tanks quickly. While it’s not the best idea to cycle a tank with fish in it, many nano tank suitable fish have a high survivability rate during a fish-in cycle. The Scarlet Badis will die before the tank is cycled. Only add them to an established tank.

You can substitute real plants for silk ones, but the extra water filtration from live plants will give you a more efficient system overall. 

Let’s discuss things in a little more depth for those who are new to the hobby.

Required Equipment

You’ll need the following:

  • 10+ Gallon Aquarium
  • Nutritious Substrate
  • Hardscape Elements (Rock or Driftwood)
  • Hang-on-Back Filter Appropriate for Tank Size
  • Heater
  • Aquarium Test Kit
  • Water Conditioner

That’s enough to get the tank started.

Optionally, you may also want a low-powered (for tank size) sponge filter and an air pump. Use them as a supplement to keep nitrates down since Scarlet Badis need very clean water.

The other big option to consider is a CO2 generator. CO2 generators boost your plant’s growth and lower pH in the water. That latter bit can be important depending on your local tap water.

Using RO/Distilled Water

Your Scarlet Badis will be fine in most tap water, but you should still test pH at the tap. If you’re routinely over 8.0 then you may need to use reverse osmosis or distilled water for your tank’s base.

You can check consumer confidence reports to get a rough idea of your local tap water. If your starting pH is over 8.2 then you may want to consider a purer option. Likewise, for water hardness, anything over 20 dGH may need to be softened.

Plant Ideas

Plants are important for your Badis, and the main non-equipment addition to the tank along with the hardscape. Use them to create a great environment from the start.

If you’re not an aquatic green thumb, I’d suggest the following arrangement:

  • Java Moss-Tied to Driftwood or rocks to start with. Allow it to spread, you can just cut it back with scissors when necessary. Use it to cover any “cave” entrances and as a general mid-water plant to provide a secure feeling for your Badis.
  • Cryptocoryne Wenditii– Spread around the bottom of the tank, Crypts provide a nice “jungle” look that also allows your fish to feel very secure. Use root tabs once your substrate is depleted or they’ll die back.
  • Vallisneria sp. Vallisneria is another easy plant for a beginner that spreads well. You can allow it to grow along the top as well, creating an easy-to-control “floating” plant at the top of the tank.
  • Anubias sp.Anubias are a staple for beginning aquatic botanists. They’re hardy, fish don’t eat them, and they grow unstoppably. More importantly for the beginner: exceptionally small leaves on your Anubias mean you’re missing a nutrient in the water, usually a micronutrient that can easily be filled in with a liquid fertilizer.

The key element is coverage. Dense planting makes these little guys happy, and it’s the key to bringing out active instead of shy behavior.

And don’t forget caves. They’re often forgotten, with people assuming just plants will do it, but they appear more lively when given appropriate hiding spots made of rock or driftwood.

A Review of Fishless Cycling

Fishless cycling is the key to survival for your Badis. It’s an easy procedure, only requiring your test kit and a couple of weeks.

It doesn’t have to be a boring time period. Use the time spent cycling to establish your plants. Plants will be fine through most cycles.

Find a good spot for your test kit for a couple of weeks as well, you’re going to be making use of it once or twice a day.

  1. Feed a small amount daily through this process, even if you didn’t place any fauna in the tank.
  2. Test for ammonia 1-2x/day until it appears in measurable levels.
  3. Begin testing for nitrite after ammonia shows up. Within a few days, there should be detectable levels.
  4. Keep testing until your nitrite levels are zero. The cycle is “complete” at this point, or at least a lot less toxic.
  5. Test nitrates until they’re at a manageable level. Under 10ppm is best, but under 15ppm is fine for your Badis.

In the end, you’ll have a tank that’s biologically stable and ready for you to begin adding fish.

Scarlet Badis are not appropriate for a fish-in cycle. Fish-in cycles are in a gray area at best. In this case, you’re just going to end up with dead fish. It’s not even a question of ethical behavior. It’s just not a practical idea.

Scarlet Badis Behavior

The behavior of captive fish is never quite like that of their wild counterparts, but Scarlet Badis tend to be bold little predators in the wild. Their reputation for shyness often comes from a lack of caves, rather than being an innate trait of the fish.

Their reputation for being aggressive is also overblown in most cases. They’re feisty, but they rarely pose a threat to any other species.

That said, you should be aware of all of the following.

Overcoming Shyness

Scarlet Badis are sometimes called shy fish, especially if there are larger fish in the tank. While the majority of larger fish can eat a Badis easily, there shouldn’t be an issue with most smaller fish.

To keep active behavior, you need cover and caves. The fish will launch regular raids around the tank looking for delicious microfauna and be particularly active around their favorite cover area in the tank.

If your Scarlet Badis are still shy despite having a lot of cover, consider their tankmates. Anything too big or active will make them hide and should be transferred to another tank. Scarlet Badis do best in a species only aquarium, balancing tank mates takes time and expertise.

Male Aggression

Many people assume Badis are cichlids due to their “aggressive” nature. They’re not on that level and are fine with similarly sized fish like Endler’s Livebearers. 

Be aware that the Badis will eat fish fry, so livebearers are a bad route in some cases.

A safe level of stock is one male per ten gallons. You can keep 2-3 females per male. Some people report higher stocking levels, but if you’re going to make the attempt you need a lot of foliage and caves.

When breeding, the footprint of the aquarium is the biggest concern. Remember that these fish rarely live deeper than 36” but they live in a lot of water as well. Each fish will claim a territory, which usually ends up being about 6” x 6”. 

Determining Sex

Dario dario is sexually dimorphic. The males and females have their own identifying traits.

The problem is that female Scarlet Badis can be hard to find. You usually buy the fish as juveniles and they’ll need to be adults to know 100%.

Females reach ½” long and have duller coloration than males. The size difference is the best indicator in an adult population since the females can have good coloration as well.

In a nano-tank, this can be a problem. Males will tend to fight each other in enclosed spaces, and will even kill each other if things are too tight. Your local fish store may be able to help, and you can also find them by sex online occasionally.

Just be careful when choosing fish and be ready to return extra males. Finding the right male-to-female ratio can take time, but it’s important for the future health of the aquarium.

Suitable Tankmates

Scarlet Badis are usually kept in species-only tanks, but you can place them in the right community tank as long as you’re careful.

You’re basically looking for fish under 2” with a peaceful temperament and nature. 

If you’re already familiar with nano aquaria, you’ll find most smaller species are fine to stock alongside the Dario dario. The following are some examples:

A peaceful nature isn’t quite enough: you want fish that aren’t overly active as well. 

A good example of what not to keep is Zebra Danios. They’ve got a docile temper and fit the size requirement, but they’re very active. With that big of a size difference, a few Zebra Danios charging around the tank are enough to keep them hiding.

Consider carefully if you want to create a community tank. A species-only tank is the best option for Scarlet Badis and you’ll have to build the entire community around them.


Invertebrates are an essential part of any aquarium system designed to function long term. Scarlet Badis, however, are micro predators which will make things a little more complicated than dropping in a few snails and ghost shrimp.

Due to their small size, Scarlet Badis don’t pose much of a threat to adult snails. They can eat the baby snails that emerge whenever you have snails in the tank, however.

If you have a choice, I recommend keeping Malaysian Trumpet Snails with your Scarlet Badis. With a sandy substrate they’ll be protected from the fish most of the time, they aerate the substrate, and they’ll eat a bit of detritus. 

Ramshorns and Pond Snails will be very vulnerable just after hatching. That leads to declining populations if you don’t seed the tank with enough snails.

Otherwise, most small snail species will do. You can also add Apple Snails or Mystery Snails to the mix at a rate of 1 per 5 gallons.

Most planted tank keepers use shrimp in their tanks. You have two choices:

  1. Cherry Shrimp or Ghost Shrimp
  2. Amano Shrimp

Cherries are available in a ton of color morphs these days and they’re very low maintenance. Most tank owners want them to breed, which can be a problem in a Scarlet Badis tank. The adults are safe from the smaller fish but the shrimplets are exactly what a Scarlet Badis hunts for. 

Ghost shrimp care is mostly the same, but there’s no guarantee of finding the right species. A ton of different micro shrimp species are sold as “Ghost Shrimp.” One of these, the Whisker Shrimp, is an opportunistic predator that’s larger than a Scarlet Badis. They’re actually classified as freshwater prawns rather than shrimp.

You can see where problems might emerge for those unsure of the difference.

So it’s a matter of keeping a heavily planted tank and enough shrimp to outbreed the appetite of the Scarlet Badis in the tank. The system will balance somewhere once you have enough shrimp in the tank.

Amano Shrimp are more long-lived and among the most dedicated algae eaters. The adults are large enough to avoid being eaten by the Badis and they’re rarely bred in captivity. Just make sure you bring home shrimp that are at least the size of the Badis.

The other common aquarium shrimp is the Bamboo Shrimp. They’re too big and have specialized care requirements that make them unsuitable.

Specialized Care Requirements

Scarlet Badis are considered an intermediate fish, not truly suitable for most beginners. That said, they only require a couple of special points of care. 

If you’re aware of them you can keep these fish successfully, you don’t need to be an expert.

Growing Plants

Naturally planted aquariums are attractive, but not everyone has a green thumb.

There are only a few points of failure in a planted aquatic system for the majority of plants. If you’ve never kept them before, here are some quick guidelines:

  • Use a Fertilizer- Use a liquid fertilizer for your plants. I prefer to only dose micronutrients through liquid fertilizer and use root tabs for long-term rooted plant growth.
  • Use a Nutritious Substrate- The “standard” for most people is Flourite, but there’s a lot of variety out there. As long as you don’t want neon colors, you can find most natural shades in a suitable format (ie: black sand). Most will give you about 6 months of a headstart on requiring root tabs.
  • CO2 Generator or Booster- Use a CO2 booster (ie: SeaChem’s Excel) or generator if you have good lighting.
  • Regular Good Lighting- 1W (or 50 Lumen) per gallon is enough for most green plants. Any less and you won’t have much success if you go over 1.5W/75 Lumen per gallons CO2 becomes a requirement. 

Hot Tip: Above, I recommended Cryptocoryne Wenditii as an ideal plant to pair with Scarlet Badis. One thing to be aware of with Cryptocoryne species is their susceptibility to “Crypt Melt.” It’s not nearly as horrifying as it sounds, Cryptocoryne species shed leaves quickly when water conditions change.

The leaves will usually turn brown and then begin to rot. Check for new growth if a recently added Crypt seems to be dying. If you’ve got new leaves coming from the rhizome then you don’t need to take action.

Live Food Cultures

Scarlet Badis are notorious for not taking dead foods, which is the biggest hurdle in their care.

Observe your fish carefully to make sure that they are eating. If they’re just picking through or ignoring the usual foods, like frozen bloodworms, you’ll need to get them something alive.

My recommendation for someone with no experience keeping live food?

Go with daphnia or brine shrimp. Both are easy to care for and only require minimal amounts of effort.

Daphnia species are quite easy to keep. They’re large filter-feeding zooplankton and readily available. They’re cultured for all kinds of experiments, but the general basis of their care is the same.

I recommend purchasing a commercial culture and working from there. Most of them will also come with algae either contained in the same container or to be seeded elsewhere. “Green water” is one of the best food sources for Daphnia but you can also feed them spirulina powder.

Brine shrimp are a little more labor-intensive, but you can buy a full hatchery online. The biggest difference is just setting up aeration. Simple models of DIY hatcheries don’t need anything more complex than a plastic bottle, air pump, and some air tubing.

Brine shrimp also need to be thoroughly rinsed in fresh water before being fed to the Badis.

Tubifex worms are also relatively easy to culture but grow in filthy water and a mismanaged colony will become a disgusting mess of stench and rot in short order.

Breeding Scarlet Badis

Scarlet Badis are very easy to breed as long as you’ve met their needs in the first place.

They’ll breed fairly non-stop in most qualities of water. Lack of cover is one of the few things that will stop them.

Keep breeding in species-only tanks. Other species will eat them, and some will even eat the eggs. Your best chance at any of the fry making it to adulthood lies in keeping them away from other fish.

In an established tank, the male will soon begin a courtship ritual. They dance a bit, they mate, and then the female runs off to lay eggs. 

Once the fish have mated, the female will lay her eggs underneath the leaves of a plant. Broad-leaved plants seem to be preferred, but they’ll also use moss and even the underside of driftwood on occasion.

The male then guards this territory. Keep an eye on the tank if you have more than one set of breeding fish in there. The males become very aggressive when protecting their eggs.

If you can, find where the eggs have been laid and remove them to a nursery tank now. If they’re hidden you can wait and it usually won’t end in disaster.

The eggs hatch in about five days, leaving behind tiny fry. While not guaranteed, cannibalism does occur with this species. Remove the fry and place them in a nursery tank as soon as possible.

The baby fish are very sluggish until about day 9, at which point they become more active. After that, it’s just a matter of observing their growth. Make sure you have a way to separate the males of the bunch as they get older.

On average, these fish will lay 70-90 eggs. Plan accordingly.

Nursery Setup and Culturing Infusoria

If you’ve taken care of fish fry before you’ll be in good hands here. Fortunately, there’s not a lot of specialization that’s required for your nursery tank.

A filter, heater, and a handful of Java Moss in a 5-10 gallon tank will make a fine nursery.

You’ll want to prepare some infusoria to feed them. It’s an easy process:

  1. Throw some vegetables in a mason jar or other glass container. Fill it about 1/4th of the way.
  2. Place distilled or boiled water in the jar, filling it up to ⅓ capacity.
  3. Fill the rest with tank water from a water change.
  4. Put it in sunlight indoors.
  5. Wait until the water gets cloudy, that’s when the initial bacteria bloom.
  6. When the water begins to clear in 2-3 days you have your infusoria.

Ideally, you’ll have the infusoria good to go ahead of time. You can just take droppers of the culture and place them in the fry tank to transfer the micro-organisms which make up infusoria. 

Continue to feed infusoria until the fish are large enough to eat smaller Daphnia or immature brine shrimp.

Small Fish, Big Impact!

With the information above, you’ll find yourself well equipped for taking care of Scarlet Badis. These small, feisty fish make a great centerpiece for nano-tanks and are an excellent challenge for a new fishkeeper who wants to expand their skill set.