Skip to content
Know your inhabitants. Start with their needs.
aquariumwebshop
Care guide · Freshwater · fish

Filament barb

Dawkinsia filamentosa

No verified species photo available yet

The filament barb (Dawkinsia filamentosa) is an active, medium-sized barb from India’s southern Western Ghats. Adults may reach about 12 cm standard length. The specialist profile recommends a tank footprint of at least 120 × 45 cm (about 243 litres) and ideally a shoal of 8–10 fish. It is therefore not a small-tank beginner fish. Provide clean, oxygen-rich water, open swimming space and a varied diet. This barb also remains fairly large and active, so do not buy a small group before arranging suitable long-term space. Let a new aquarium mature biologically before introducing the fish. The trade name “mahecola barb” may be applied to more than one Dawkinsia species, so identification deserves care.

Plan your aquarium →

At a glance

Temperature
20–25 °C
pH
6.0–7.0
GH
2–15 °dGH
Aquarium length
At least 120 cm
Minimum aquarium volume
At least 243 L
Adult size
Up to 12 cm
Group size
At least 8–10 individuals
Temperament
Peaceful

About this species

The accepted name is Dawkinsia filamentosa (Valenciennes, 1844). Older sources use combinations including Puntius filamentosus and Leuciscus filamentosus. Adult males and some females may develop filament-like extensions on the dorsal fin; this varies by population and condition. The species has a dark mark near the caudal peduncle and dark bands on the tail lobes. Identification confusion occurs within Dawkinsia, so a trade name alone is not enough to establish identity.

Natural habitat

The species is endemic to the southern Western Ghats, with records from Kerala, Tamil Nadu and possibly southern Karnataka. It has been reported from lowland coastal floodplains, rivers, estuaries, coastal marshes and reservoirs, in fresh and locally brackish water. This broad habitat description does not justify keeping it in brackish water; the aquarium conditions below follow the specialist aquarium source.

Aquarium and layout

For long-term care, the specialist source advises a footprint of at least 120 × 45 cm and approximately 243 litres. Ideally keep 8–10 conspecifics. Arrange open swimming areas with rounded rocks, sand or fine gravel, and optional driftwood. A mature, well-maintained aquarium with reliable biological filtration and high oxygenation is important. Hardy plants can be attached to wood or stone; avoid planting so densely that the shoal cannot turn freely.

Water conditions

The published aquarium range is 20–25°C, pH 6.0–7.0 and GH 2–15 dGH. No reliable KH range is established here. Prioritise stability, good aeration and low organic pollution rather than rapid repeated adjustments. The source says the fish is intolerant of pollution. It recommends routine weekly water changes of 30–50%; adapt the schedule to the aquarium, filter maturity and measured water quality.

Behaviour and group size

This is an active shoaling fish. A group of 8–10 can reduce skittishness and distribute social interactions. The source considers it suitable for a peaceful riverine community with other shoaling fish and robust tankmates too large to be prey and not easily intimidated by its activity. Do not choose companions on overlapping water values alone. No specific species pairs are presented here as verified recommendations. Watch for persistent chasing, damaged fins or fish missing meals.

Feeding

It forages as an omnivore on worms, insects, crustaceans, plant matter and other organic material. Use a complete quality food as the staple, such as suitable flakes or granules, and regularly offer small portions of frozen or live foods such as Daphnia, Artemia or insect larvae. Vary the diet, feed only what the shoal will eat promptly, and remove leftovers to protect water quality.

Breeding

Dawkinsia filamentosa is an egg-scattering free spawner with no parental care. Fry may occasionally appear in a mature aquarium, but adults will eat accessible eggs. For a deliberate attempt, the specialist source describes a separate dimly lit spawning tank with fine mesh, marbles, spawning mops or fine-leaved plants to protect the eggs. It reports hatching in 24–48 hours and free swimming about a day later; these are approximate source timings, not a guarantee. Newly hatched fry need microscopic food.

Sources & review

This care guide draws on several specialist sources and was last checked on .

View the sources