Mascara Barb - Dawkinsia Assimilis

Mascara Barb | A Striking and Active Schooling Fish From the Western Ghats of India

The Mascara Barb (Dawkinsia assimilis) is one of the most visually impressive and underappreciated barbs in the freshwater aquarium hobby. Native to the fast-flowing, well-oxygenated rivers and streams of the Western Ghats in southwestern India — including the Chalakudy, Kallada, and Netravati River basins — this large, torpedo-shaped barb is a genuinely stunning fish that commands attention in any spacious community aquarium. Its metallic silver body is accented with a bold dark lateral stripe, warm orange-silver and rose tones, and the distinctive black marking behind the eye that gives this species its evocative common name.

Breeding males are in a class of their own — developing vivid red-orange accents on the dorsal and caudal fins, extended filament-like fin rays, and small tubercles on the head that signal peak condition. In a large school under good lighting, the Mascara Barb is nothing short of spectacular.

Mascara Barb Care Guide

Care at a Glance

• Scientific name: Dawkinsia assimilis
• Also known as: Mascara Barb, Mascara Torpedo Barb, Blackline Barb, Redfin Mascara Barb
• Origin: Western Ghats, southwestern India
• Adult size: 4–5 inches (10–13 cm)
• Minimum tank size: 55 gallons (200 litres) — longer tanks strongly preferred; minimum 47 inches (120 cm) frontage recommended
• Temperature: 72–79°F (22–26°C) — a cooler water species that prefers the lower end of the tropical range
• pH: 6.5–7.5
• Hardness: 5–15 dGH — soft to moderately hard water
• Strong filtration and high oxygenation essential
• Best kept in groups of 8 or more
• Lifespan: 5–8 years with good care

Mascara Barb Tank Setup

A spacious aquarium with strong water flow, excellent oxygenation, and plenty of open swimming space suits these fish perfectly — reflecting their natural fast-moving river habitat in the Western Ghats. Fine sand or smooth gravel substrate, rocks, boulders, driftwood, and hardy plants such as Java Fern and Anubias provide structure and cover while leaving plenty of open water for the school to move freely. A filter providing 4–5 times the tank volume per hour is recommended to maintain the well-oxygenated conditions this species thrives in.

Feeding Your Mascara Barbs

Omnivores with a healthy appetite. A high quality flake or pellet forms an excellent staple diet, supplemented regularly with frozen or live foods such as bloodworm, brine shrimp, and daphnia. Variety is important for maintaining their vibrant colouration and long term health — a diet rich in colour-enhancing foods will bring out the red-orange tones in males particularly well.

How Many Mascara Barbs Should You Keep?

As a true schooling species, Mascara Barbs should always be kept in groups of 8 or more. In a proper school they are active, confident, and display their most impressive behaviour and colouration. Males in particular become more boisterous and competitive in larger groups — chasing one another and displaying their finest colours in a constantly dynamic and entertaining show.

Mascara

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Mascara Barb | A Striking and Active Schooling Fish From the Western Ghats of India

The Mascara Barb (Dawkinsia assimilis) is one of the most visually impressive and underappreciated barbs in the freshwater aquarium hobby. Native to the fast-flowing, well-oxygenated rivers and streams of the Western Ghats in southwestern India — including the Chalakudy, Kallada, and Netravati River basins — this large, torpedo-shaped barb is a genuinely stunning fish that commands attention in any spacious community aquarium. Its metallic silver body is accented with a bold dark lateral stripe, warm orange-silver and rose tones, and the distinctive black marking behind the eye that gives this species its evocative common name.

Breeding males are in a class of their own — developing vivid red-orange accents on the dorsal and caudal fins, extended filament-like fin rays, and small tubercles on the head that signal peak condition. In a large school under good lighting, the Mascara Barb is nothing short of spectacular.

Mascara Barb Care Guide

Care at a Glance

• Scientific name: Dawkinsia assimilis
• Also known as: Mascara Barb, Mascara Torpedo Barb, Blackline Barb, Redfin Mascara Barb
• Origin: Western Ghats, southwestern India
• Adult size: 4–5 inches (10–13 cm)
• Minimum tank size: 55 gallons (200 litres) — longer tanks strongly preferred; minimum 47 inches (120 cm) frontage recommended
• Temperature: 72–79°F (22–26°C) — a cooler water species that prefers the lower end of the tropical range
• pH: 6.5–7.5
• Hardness: 5–15 dGH — soft to moderately hard water
• Strong filtration and high oxygenation essential
• Best kept in groups of 8 or more
• Lifespan: 5–8 years with good care

Mascara Barb Tank Setup

A spacious aquarium with strong water flow, excellent oxygenation, and plenty of open swimming space suits these fish perfectly — reflecting their natural fast-moving river habitat in the Western Ghats. Fine sand or smooth gravel substrate, rocks, boulders, driftwood, and hardy plants such as Java Fern and Anubias provide structure and cover while leaving plenty of open water for the school to move freely. A filter providing 4–5 times the tank volume per hour is recommended to maintain the well-oxygenated conditions this species thrives in.

Feeding Your Mascara Barbs

Omnivores with a healthy appetite. A high quality flake or pellet forms an excellent staple diet, supplemented regularly with frozen or live foods such as bloodworm, brine shrimp, and daphnia. Variety is important for maintaining their vibrant colouration and long term health — a diet rich in colour-enhancing foods will bring out the red-orange tones in males particularly well.

How Many Mascara Barbs Should You Keep?

As a true schooling species, Mascara Barbs should always be kept in groups of 8 or more. In a proper school they are active, confident, and display their most impressive behaviour and colouration. Males in particular become more boisterous and competitive in larger groups — chasing one another and displaying their finest colours in a constantly dynamic and entertaining show.

Mascara Barb Tank Mates

• Other large, active barbs such as Denison Barbs and Tiger Barbs
• Rainbowfish and similarly sized active schooling fish
• Larger gouramis and peaceful medium to large community fish
• Loaches and peaceful bottom dwellers
• Avoid small, slow-moving, or delicately finned fish that may be stressed or nipped by their boisterous activity
• Avoid very small fish that may be outcompeted for food

 Tank Mates

• Other large, active barbs such as Denison Barbs and Tiger Barbs
• Rainbowfish and similarly sized active schooling fish
• Larger gouramis and peaceful medium to large community fish
• Loaches and peaceful bottom dwellers
• Avoid small, slow-moving, or delicately finned fish that may be stressed or nipped by their boisterous activity
• Avoid very small fish that may be outcompeted for food