Mascara Barb (Dawkinsia assimilis) – Keeping Feeding Breeding

Mascara Barb

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The Mascara Barb is one of those fish that, as soon as you see them, you want them. It amazes me more fish stores don’t sell them.

These peaceful, schooling barbs make an excellent addition to a community tank. They are an active species of fish that is always swimming around the tank, looking for food, or generally investigating their surroundings.

Overview of Mascara Barbs

Mascara Barbs (Dawkinsia assimilis) originate from Southwest India and were first described in 1849 by Thomas C. Jerdon who was a British physician, zoologist, and botanist.

The Mascara Barbs scientific name, Dawkinsia assimilis is named after Richard Dawkins, for ‘his contribution to the public understanding of science and, in particular, of evolutionary science’.

Mascara Barbs are peaceful fish that school loosely when swimming around the aquarium. They are a breed of fish that fits well into a peaceful community aquarium setup. The males offer more color than the females, especially when spawning time comes around

I have been keeping the Mascara Barb for around 5 years, and I wish I had started keeping them sooner. They are fish that never fail to impress anyone who comes into my fish room.

Mascara Barb Characteristics

Common Name:Mascara Barb
Scientific Name:Dawkinsia assimilis 
Origin:Southwestern India
Tank Distribution:Mid-water
Adult Size:3.5″ – 4.5″ (9cm – 11.5cm)
Life Expectancy:4-6 years
Care Level:Easy
Minimum Tank Size:75-gallons (285 liters)
Breeding Method:Egg scatterer
Temperature:66°F – 78°F (19°C – 25.5°C)
pH:6.0 – 7.0
Hardness:35 – 185ppm

Mascara Barb Origins

Mascara Barb Origins Map

Mascara Barb Habitat

The exact range of the Mascara Barb is currently poorly understood. Researchers say more work is required to find out exactly how far their range extends.

To date, specimens have been found in both sluggish, slow-moving rivers which had distinctively muddy river beds as well as faster flowing rivers where the water was clear and the river bed was rocky and compromised well-worn boulders and gravel.

There is some speculation in the scientific community that location may vary depending on the time of year. In 2005 specimens were found in the Kallada River where the water was clear and less than 20″ (50cm) deep.

Are Mascara Barbs Captive Bred or Wild Caught?

Mascara Barbs are fairly easy to breed in captivity and there are a number of farms in the Far East that breed and export these fish to the US. A number of wild-caught specimens still find their way into the trade.

The International Union for Conservation of Nature and Natural Resources (ICUN) currently lists the Mascara Barbs status in the wild as vulnerable, and wild populations are at risk from farming for the aquatic trade and pollution.

Mascara Barb General Description

Mascara Barbs are slender fish whose body has developed over generations to allow them to zip through the water effortlessly.

These elegant fish, which only reach around 4″ (10cm) in length, are deceptively colorful with blue to purple coloration running through their fins and an almost pearl-like green color running across the top of their golden bodies. Mascara Barbs also boast a brightly colored section just behind the eye, giving rise to the common name.

When you see Mascara Barbs in the store, they may not show the brilliance of their full color. But once you get them home, settled, and eating a high-quality diet, you will not be disappointed.

When I first purchased my Mascara Barbs, I brought home a bag of fairly drab-looking silvery fish. However, within a month of being in my fish room, they showed their amazing colors and they haven’t stopped showing off since.

Mascara Barb

Are Mascara Barbs Aggressive?

The trouble with any fish that has the word barb in its name, is everyone always assumes it is going to have the fin nipping reputation of the Tiger Barb.

In my experience, I would not consider Mascara Barbs to be an aggressive species of fish.

I have barely witnessed any behavior I would class as aggressive. In fact, I would say the Mascara Barb is better suited to a peaceful community tank rather than one where it is going to have to fight for its place.

Please be aware, I keep a good-sized group of Mascara Barbs which means the males always have females to dedicate their attention to. If you just keep 1 or 2 Mascara Barbs in a tank, they may behave differently.

Mascara Barb Tank Setup

As mentioned above, Mascara Barbs have been found in varying locations with different natural habitats. As such it can be tricky to decide what is the best setup.

The following setup suggestion is based on my experience of keeping this fish. It may be they are just as happy in a different setup.

Mascara Barb Tank Size

Mascara Barbs are active swimmers and they spend much of their day going from one side of the tank to the other, then back again. They never seem to stop moving.

Bearing their activity levels in mind, the smallest tank I would suggest you keep a school of these fish in is a 75-gallon (285 liters) tank. These tanks usually measure about 4′ (120cm) wide which gives the Mascara Barbs a decent swimming length.

As with almost any fish in the hobby, bigger is always better and these fish certainly aren’t going to complain if you provide them with more space.

Mascara Barb Substrate

Mascara Barbs spend the majority of their time mid-water. Whilst they will pick the occasional bit of food off the bottom of the tank, I don’t believe they are overly concerned about what substrate they have in their aquarium.

In my own Mascara Barb tank, I have mixed some pea shingle with this sand that I ordered from Amazon. It looks natural in my opinion, and the mix of sand and gravel allows live plants to grow.

No matter what substrate you choose, make sure you can gravel vacuum it on a regular basis. Mascara Barbs are fairly intolerant of poor water conditions. Uneaten food and fish poop breaking down in the substrate can cause nitrate levels in the aquarium to rise.

Decorations in a Mascara Barb Tank

Much like with substrate, I don’t believe these confident, outgoing fish need caves and places to hide, and as such, I don’t think the choice of aquarium decoration is important.

If you want to add some fake plants to your Mascara Barb tank, then the addition of dark green color will certainly make the Mascara Barbs’ own colors really pop. I have used these fake plants to great effect in a number of my aquariums.

Researchers have found that the river and stream beds where Mascara Barbs are naturally found often have large quantities of rocks and rounded boulders as well as roots and fallen branches. As such, these are what I have added to my own Mascara Barb tank to give it a natural feel.

Best Live Plants for Mascara Barbs?

Whilst Mascara Barbs wouldn’t be described as ‘plant eaters’, they will certainly take the occasional nip at plants, especially the less tough varieties.

As such, you will want to select plants that can take a little rough and tumble without worry they are going to die. I have had good success using the following plants in my Mascara Barb tanks;

Each of the plants above can take the occasional nip. Some of them like to be planted in the substrate, whereas others want to be tied to a rock or piece of wood where they will attach themselves over time.

Filtering a Mascara Barb Tank

As discussed above, Mascara Barbs are fairly intolerant of poor water quality. As such, filtration is very important. Mascara Barbs also seem to enjoy a bit of flow in their tanks, so a filter that turns the water over several times an hour is ideal.

I have had great success in recent years using the AquaClear hang-on-back filters. I have found them easy to service, fairly reliable and you can customize the media in them, allowing you to tailor the filter to the tank’s needs.

Heating a Mascara Barb Tank

Mascara Barbs are tropical fish and as such they want their aquarium water to be between 66°F and 78°F (19°C and 25.5°C). Keeping them at temperatures much above or below this range will cause the fish to become stressed and susceptible to pests and diseases.

I currently use a lot of the E-Series of heaters that are made by Fluval. They are a little more expensive, but they seem to be very accurate and easy to adjust to the correct temperature, plus they have a digital screen displaying the current temperature and warning you if the water is too hot or too cold. You can check the price of these heaters on

Lights for a Mascara Barb Aquarium

There is no doubt in my mind, to fully appreciate Mascara Barbs you need a good quality aquarium light. I am really enjoying using the Aquasky light on a number of my tanks. The fish look great under it, and the plants grow well.

Mascara Barb Water Parameters

Mascara Barbs do not do well when there is a lot of dissolved organic matter in their tank water. They like their water to be pristine, and they certainly like their water parameters to be stable. Stable is often better than perfect when it comes to fish keeping.

My recommendations on water parameters for Mascara Barbs are as follows;

  • Temperature: 66°F – 78°F (19°C – 25.5°C)
  • pH: 6.0 – 7.0
  • Hardness: 35 to 185 ppm

If you are unsure of your aquarium water parameters, invest in a good quality water test kit. I currently use the API Master Test Kit as it measures pH, Ammonia, Nitrite, and Nitrate. I have found it to be the most accurate test kit for the money. You can check the current price of the API Master Test Kit on here.

What do Mascara Barbs Eat?

Mascara Barbs are omnivores, meaning their natural diet is made up of both meat and vegetable matter.

In the wild, Mascara Barbs eat a lot of worms, insects, water bourne crustaceans, algae, and plant material, as well as other organic debris.

In the aquarium, there is a wide range of foods we can feed our Mascara Barbs. Mascara Barbs really want to eat their food mid-water. They prefer to eat as the food descends through the water column. As such, slow sinking foods are ideal.

I like to feed my Mascara Barbs as wide a variety of food as I can. Below I have listed some of the foods I currently feed my Mascara Barb tank;

  • Fluval Bug Bites
  • Vibra Bites from Hikari
  • Xtreme Krill Flakes
  • TetraMin Tropical Flakes

I try and give a different dry food every time I feed my tank. The theory is, the higher the number of different foods I feed my fish, the greater the range of vitamins and minerals they will have access to.

As well as feeding commercially available foods, I also try and feed my Mascara Barabs a lot of live and frozen foods. Some of the live and frozen foods I give my Mascara Barbs includes;

  • Bloodworms
  • Daphnia
  • Mosquito Larvae
  • Brine Shrimps

How Often Should You Feed Mascara Barbs?

When it comes to feeding my Mascara Barbs, in fact, when it comes to feeding almost all my fish, I find feeding little and often is better than feeding a large quantity in one go.

I aim to feed my Mascara Barbs 3 or 4 times a day, starting with pellet food in the morning, followed by flake food in the early afternoon. In the evening I try and feed either live or frozen food (although it is usually frozen as I don’t have a good live food source close to where I live), then the last thing at night I feed pellets again if my schedule allows for it.

Feeding fish little and often is not only better for your fish’s digestive system, but it is also better for your filter as it spread the fish waste out over the whole day. Plus, every time you feed your fish you naturally interact with the tank, meaning you are more likely to spot problems either with the fish or the equipment in the tank.

How Much Should You Feed Mascara Barbs?

The ‘How much should I feed?’ question is one that crops up at every aquarium club talk I give. It is tricky to answer because the answer is to feed as much as they will consume within 1 to 2 minutes.

I would suggest, that whatever food you are feeding, put a small pinch into the tank. If they eat it quickly, add another small pinch. Repeat two or three times until some of the fish begin to lose interest in the food. At this point stop, then feed the tank again later in the day.

How to Breed Mascara Barbs?

Mascara Barbs are a fairly easy species of fish to breed in the home aquarium. In fact, there are numerous reports around the internet of people finding their Mascara Barbs spawned in the community aquarium and the first the fishkeeper knew of the spawning was when baby fish started to appear in the tank.

Mascara Barbs are egg scatterers and take no parental responsibility for either the eggs or the subsequent baby fish.

When Mascara Barbs spawn, the female releases dozens, possibly hundreds of eggs into the water and the male Mascara Barb swims in and out of the cloud of eggs, fertilizing them as they fall through the water column.

Sexing Mascara Barbs

Mascara Barbs ARE sexually dimorphic, meaning you can tell which are the males and which are the females, just by looking at them.

Male Mascara Barbs develop much more intense coloration than the females, especially when it is time to spawn. They also develop breeding tubercles (small white spots, often referred to as breeding stars) on their heads when they are ready to spawn.

Female Mascara Barbs show less intense coloration. They also tend to grow a little larger and fuller in the body, especially at breeding time.

Conditioning Mascara Barbs to Breed

To get the best breeding performance from your Mascara Barbs, you need to feed them lots of high-quality foods in the lead-up to spawning.

I fed my Mascara Barbs almost exclusively on live and frozen bloodworms, Daphnia and Mosquito Larvae for about 10 days prior to spawning.

This high protein diet helps the females develop eggs and the male develop sperm. The better condition your fish are in prior to spawning, the better spawn and the more eggs you will get.

Mascara Barb Spawning Setup

Whilst Mascara Barbs will occasionally spawn in the community tank, and you may find a handful of the babies make it to the size they can swim freely in the aquarium, your success rate will be much higher if the fish spawn in a dedicated spawning tank.

The best setup for breeding Mascara Barbs would be a bare bottom tank with a small sponge filter and a heater.

Place a large clump of Java moss or an artificial spawning mop in the bottom of the tank, or better still, place a grid over the base of the tank so the fertilized eggs can fall through out of reach of the adults.

There is no need to have an overhead light on a spawning tank.

The water in the spawning tank should ideally be somewhere between slightly acidic and neutral and the temperature should ideally be in the high 70’s, maybe as high as 80°F (26.5°C).

Mascara Barb Spawning

When the spawning tank is ready and the Mascara Barbs have been conditioned with good quality live or frozen foods, place either 1 or 2 pairs in the spawning tank, or if space allows, place 6 or 7 males and an equal number of females in the spawning tank.

Spawning usually happens at dawn, so once the fish are in the tank and settled, cover the tank with a towel or thick cloth to exclude all light.

In the morning, remove the cover, allowing light into the tank. If the Mascara Barbs are ready, spawning should begin almost immediately, and certainly within an hour or two of ‘dawn’.

The females will release large clouds of eggs and the males will swim in and out of those clouds, fertilizing the eggs as they go. The eggs will drop to the bottom of the tank, either into the Java Moss or spawning mop or through the grid that has been placed to separate the adults from the eggs.

Raising Baby Mascara Barbs

The eggs usually hatch within 24 to 48 hours, depending on water temperature and the fry become free-swimming about 24 hours after hatching.

Baby Mascara Barbs require microscopic food such as infusoria, moving on to very small food like Vinegar Eels, Microworms and then newly hatched Brine Shrimp.

It takes a lot of effort and dedication to raise baby Mascara Barbs, but the effort is worth it.

Mascara Barb Tank Mates

In my experience, Mascara Barbs really are peaceful fish. Even though they have the word Barb in their name, they are not going to go around nipping the fins of all the other tank inhabitants.

I keep my Mascara Barbs in a large community-style setup with many of the following fish;

Neon Tetras

Neon Tetras

Neon Tetras make excellent tank mates for Mascara Barbs. I have a large school of Neon Tetras with my smaller school of Mascara Barbs, and the color of the Neon Tetras really does bring out the more subtle colors on the Mascara Barb.

Neon Tetras work especially well as they require almost identical water to the Mascara Barbs and they essentially eat the same food.

Cherry Barbs

Cherry Barbs
Cherry Barbs

Cherry Barbs are another peaceful member of the Barb family and they work really well with their slightly larger cousins. Cherry Barbs will school loosely with the Mascara Barbs, and their colors complement one another.

Like Mascara Barbs, Cherry Barbs do best when kept in groups of 6 or more.

Clown Loaches

Clown Loaches

I think Clown Loaches have to be one of my all-time favorite fish. They work really well with Mascara Barbs for two reasons. Firstly, Clown Loaches want to occupy the bottom area of the tank, whereas the Mascara Barbs went to spend their time mid-water. Also, both species of fish appreciate neutral to slightly acidic water, and both species of fish like a heavily planted setup.

Harlequin Rasboras

Harlequin Rasboras

Harlequin Rasboras are another fish that have natural coloration to complement the Mascara Barbs.

Harlequin Rasboras are a loose schooling fish, with individuals preferring to stay with their own kind, but they don’t form tight groups swimming back and forth together. In my own tank, the Harlequin Rasboras will often join the Mascara Barbs as they swim from one end of the tank to the other and back again.

Bristlenose Plecos

Bristlenose Pleco

Anyone who has ever heard one of my fish club talks will know I sing the virtues of Bristlenose Plecos in almost every talk. I firmly believe almost every tank should have a Bristlenose Pleco in them.

Bristlenose Plecos will keep the majority of the tank clear of algae, they will eat any food that remains uneaten on the aquarium floor, and they go about their day not interfering with any of the other tank inhabitants. They are possibly the perfect tank mate!

Rummy Nose Tetras

Rummy Nose Tetras

If I could only ever keep one fish for the rest of my life, it would probably be the Rummy Nose Tetras. I currently have a large school of them in my 155 gallons (600 liters) planted tank.

Rummy Nose Tetras are super peaceful, making them an ideal tank mate for Mascara Barbs, plus their bright red noses are indicators of aquarium water conditions. If water conditions deteriorate and the Rummy Nose Tetras aren’t happy, their noses lose all their color. A great early warning system to let you know something is wrong.

Pygmy Corydoras

Pygmy Corydoras

Unlike the vast majority of the Corydoras family, Pygmy Corydoras do not find themselves confined to the aquarium floor. Instead, they can quite often be found swimming mid-water.

Pygmy Corydoras do best when kept in groups of 6 or more, so keeping a school of them with a school of Mascara Barbs works really well. Pygmy Corydoras have very subtle coloration, which will make the brighter colors of the Mascara Barbs stand out even more.



For many, the thought of keeping a Barb with Angelfish fills them with horror. In fact, you will find a number of articles on the internet that say you can’t keep Mascara Barbs with Angelfish. The truth is, you can. The Mascara Barbs will take no notice of the Angelfish and there certainly is no need to worry that the Mascara Barbs will nip the Angelfish’s fins.

Silver Tip Tetras

Silver Tip Tetras

Silver Tip Tetras are one of the tightest school fish in the hobby. One of the most visually appealing tanks in my fish room is a 200-gallon (750 liters) tank with over 200 Silver Tip Tetras living in it.

Mascara Barbs work really well with Silver Tip Tetras as both species are very peaceful, both species like similar water conditions and both species will school as one when kept in a large enough tank

Dwarf Gourami

Dwarf Gourami

The Dwarf Gourami is one of the most peaceful fish you could ever hope to keep. A small group of males and females kept with a small group of Mascara Barbs will give you a tank full of color, movement, and harmony. This is a combination you won’t be disappointed to have.

Mascara Barb Tank Mates to Avoid

Clearly, the list of tank mates to avoid could be almost infinite. However, rather than write a list of fish, I would suggest you try to avoid larger, more boisterous South American Cichlids like Oscars, Jack Dempsey’s, and Convict Cichlids.

I would also suggest you steer clear of any fish that are known to be food aggressive and many dominate the food before the Mascara Barbs can eat it. Fish like Zebra Danios, goldfish, or African Cichlids.

Common Mascara Barb Pests and Diseases

I have to say, in my experience with these beautiful fish, I haven’t found them to be any more or less susceptible to pests and diseases.

With that said, there are a few common issues Mascara Barbs can suffer with. Some of the ones you are most likely to come across are;

  • Ich (Whitespot)
  • Fin rot
  • Dropsy
  • Internal Tapeworms

Ich (Whitespot)

Goldfish with Ich
Ich (Whitespot)

Ich, which is often called Whitespot in Europe, is probably the most prevalent disease in the hobby. A single fish infected with Ich can quickly infect an entire tank.

Ich starts off as a few spots, usually on the fins or tail, but can quickly spread. In fact, the spots are cysts caused by the parasite burrowing under the scales of the infected fish.

Ich is highly infectious, but also easily treatable with the correct medication. I have always found Ich-X which is made by Hikari to be the most effective treatment for fish that have Ich.

Fin Rot

Fin Rot

Fin rot is caused by a bacterial infection that literally eats away at the fish’s fins and tail. The major cause of fin rot is poor water quality.

Fin rot starts off with the end of the fins or tail looking like they have little bits missing. If left untreated the fins quickly start to look raggedy followed by the development of red, sore patches. Eventually, the fins and tail will rot away completely leading to the death of the fish.

Fin rot is almost completely preventable by keeping water quality high by changing large portions of water on a regular basis. If your fish suffer from fin rot, try treating them with an anti-bacterial medication.


Dropsy Goldfish

Dropsy is a catch-all term given to fish that swell up due to excess fluids in the body cavity. Dropsy can be caused by internal bacteria such as Aeromonas bacteria or by kidney failure.

The prognosis for fish suffering from Dropsy is generally not good. There are treatments for internal bacteria such as KanaPlex which is made by Seachem. Treatment needs to be swift after diagnosis, but the outcome is far from certain.

Internal Tapeworms

Internal Tapeworms live inside the digestive system of the fish. They consume all the goodness from the fish’s food before the fish can. Mascara Barbs that have internal tapeworms can literally starve to death even though they eat every day.

In my experience, it is best to assume all new fish coming into your care have internal tapeworms and treat them accordingly.

I have had the best luck using Paracleanse to treat my fish for internal tapeworms. Paracleanse paralyzes the tapeworms, causing them to pass when the fish goes to the bathroom.

My Final Thoughts on Mascara Barbs

Mascara Barbs are truly fascinating fish. They are super peaceful, bring subtle yet bright color into the tank and they can even be bred in the home aquarium, possibly then selling the baby fish for a profit.

If you are looking for something new to keep, and you don’t mind putting in a bit of effort to find them, consider adding Mascara Barbs to your tank. You won’t regret it.

About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James

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