Maximum size : 12 cm

Mascara Barb - Dawkinsia Assimilis : Complete Fish Profile & Care Guide

Table of contents


Meet the fascinating Mascara Barbs (Dawkinsia assimilis), a brilliant species that makes a fantastic addition to any community aquarium. These fish are relatively peaceful and are not known for nipping fins, but be warned, they can be boisterous and active, especially the males, who love chasing each other. 

To ensure the best possible environment for your Mascara Barbs, it's best to keep them with equally large and active tankmates, such as Denison Barbs, Rainbowfish, Gouramis, Loaches, and other medium to large-sized Barbs. These fish are schooling species, so it's best to keep them in groups of at least eight or more. The more Barbs in the tank, the more comfortable and natural they will feel, and the more impressive your display will look.

When setting up an aquarium for Mascara Barbs, be sure to include various-sized rocks, pebbles, sand, or fine gravel for substrate, and perhaps some small boulders for added interest. Hardy aquatic plants such as Anubias or Microsorum, along with driftwood, will also provide your fish with plenty of hiding places and a natural feel.

Mascara Barbs have a unique appearance, with a pear-shaped black spot on the caudal peduncle, blue-black lines under their eyes, and a curved reddish-pink line resembling a thin pearl necklace on their silvery bodies. Their fins are mostly translucent, except for their bright red dorsal fins and red and black-tipped caudal fins.

Males have a more striking colour pattern, with vivid red dorsal fins and tubercules on their heads when breeding. In the end, the care and keeping of these stunning Mascara Barbs are relatively simple. Just be sure to keep them in groups, provide them with plenty of space, and feed them a balanced diet of small frozen and live foods, high-quality dried flakes, and granules, and you'll have happy, healthy, and vibrant fish.

Mascara Barb Photos

Sexual Dimorphism

It can be quite challenging to differentiate between male and female Mascara Barbs as both sexes display remarkable red colouration as mature adults. Nevertheless, males possess more striking colour patterns and develop vivid red dorsal fins and detailed dorsal filaments. They also develop tubercles on their heads during breeding. Conversely, females tend to grow larger, heavier, and comparatively duller as they age.

Quick Facts

Scientific NameDawkinsia Assimilis
Year Described1849
Other NamesRed Necklace Barb, Assimilis Barb
Max Size12 cm
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 8+
Diet & FeedingOmnivore
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.0 - 8.0
GH 5 - 15
KH 1 - 10
TDS 40 - 70
Ideal Temperature
65 - 80
18 - 27

Natural Habitat

Mascara Barbs are indigenous to the lush landscapes of Southwest India, specifically the Chalakudy, Kallada, and Netravati River Basins, in the states of Kerala and Karnataka. The Mascara Barbs are diverse creatures with various habitat preferences depending on the season and location. In the Netravati River, they prefer limited areas with sluggish flowing waters and a muddy substrate.

Conversely, in the Chalakudy River, these Barbs can be found in rocky, clear, fast-flowing, highly oxygenated stretches between waterfalls formed from the river descending from the Western Ghats Mountains. Adding these Barbs to your aquatic collection will undoubtedly enhance the beauty of your aquarium. So why not explore the wonders of Mascara Barbs and bring a little bit of Southwest India into your home today?

 Chalakudy River - India
India Flag
 Kallada River - India
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Mascara Barbs are capable of reproducing on their own in an established aquarium with proper water conditions. However, for those looking to maximize their yield of fry, a separate breeding tank is recommended, equipped with a mesh-covered bottom or filled with fine-leaved plants or spawning mops.

The breeding tank's water pH should be slightly acidic to neutral, and temperature should be kept in the upper range. Additionally, water movement and oxygenation can be provided through an air-powered sponge filter or air stone. To encourage spawning, one or two well-conditioned pairs of Mascara Barbs can be introduced into the breeding tank, and spawning will generally occur the following morning.

Alternatively, spawning can occur in a group, although a larger aquarium may be necessary. It's crucial to remove the eggs as soon as they are spotted, as adult fish tend to eat them. The eggs typically hatch within 24 to 48 hours, and the fry becomes free-swimming approximately 24 hours after that. For the first few days, the fry will require microscopic food until they are large enough to accept baby brine shrimp or microworms.

Diet & feeding

In their natural habitat, Mascara Barbs are known to consume a varied diet of insects, crustaceans, worms, plant matter, and other organic debris. However, when kept in captivity, they are not picky eaters and can be fed with ease. For optimal health and vibrant coloration of your Barbs, it is recommended to provide them with a balanced diet consisting of small live and frozen foods, including daphnia, brine shrimp, and bloodworms, in addition to high-quality dried flakes and granules. By offering this nutritious mix, you can ensure the well-being of your fish and promote their overall health.

Frequently asked questions

Mascara Barbs are one of the larger barb species kept by aquarists, growing up to 9-12cm in length.

Mascara Barbs are endemic to Kerala and Karnataka in the Southwest Indian states, where they occur in the Chalakudy, Kallada and Netravati river basins. Mascara Barbs have various habitat types depending on location and the time of year. For example, in the Netravati, they were reported in limited zones with a sluggish, almost still flow and muddy substrate. In contrast, people collected the Chalakudy fish from rocky, clear, flowing stretches between waterfalls formed from the river descending from the Western Ghats mountains.

In captivity, Mascara Barbs are not picky and are easily fed. However, you should provide your Barbs with a balanced diet comprising of regular meals of small frozen and live foods such as daphnia, brine shrimp, bloodworms, and such alongside high quality dried flakes and granules. This mix will promote the most favourable condition and colours.

It can be relatively challenging to distinguish male from female Mascara barbs as both sexes will show impressive red colouration as mature adults. However, males will typically have a more intense colour pattern and develop detailed dorsal filaments and vivid red dorsal fins and, when in breeding condition, will display noticeable tubercules on their heads. In contrast, adult females usually grow a little larger, are heavier-bodied, and less colourful than males.

Seeing as Mascara Barbs are fast-moving, aggressive feeders, it would be better to keep them with equally large and active tankmates in the aquarium. Ideal tankmates for these Barbs would be other schooling or shoaling Cyprinids such as medium to large-sized Barbs, larger Rainbowfish, Gouramis, Botiids, Cobitids, Nemacheilids, and Balitorid Loaches.

Mascara Barbs are a schooling species in nature; therefore, you should ideally keep these fish in groups of 8 or more individuals. Maintaining these Barbs in suitable numbers will not only make your fish less nervous but will also result in a more natural and effective looking display. In addition, keeping this species in larger groups will usually restrict any aggression because the males will be concentrating on maintaining their hierarchical position within the group.

Mascara Barbs have a pinky-red colouration around their snout and a blue-black line under their eyes hence their name. These fish have silvery colour bodies and display a tear-shaped black spot on the caudal peduncle. You will also notice a curved line throughout the body that almost looks like a small pearl necklace-type pattern. Most of their fins are transparent except for their tailfin with red and black tips, and their dorsal fin is a bright red colour.


Mascara Barbs - Dawkinsia Assimilis Thumbnail

9 tank mate ideas for the Mascara Barb

Looking for some awesome tank mate ideas for your Mascara Barb? Look no further! Here are 9 of the most captivating and fascinating options that will liven up your aquarium!

Other Barbs of interest