Puntius filamentosus - Filament Barb

Cyprinidae

Endemic to the Southwest Indian states of Kerala, Tamil Nadu and Karnataka and is possibly restricted to the south of the latter. The type specimens were collected close to the coastal town of Alleppey (also known as Alappuzha) in Kerala.

According to Pethiyagoda and Kottelat (2005) this species is most common in coastal floodplains. It is found in both fresh and brackish waters of rivers, estuaries, coastal marshes and reservoirs.

Fully grown at around 6"/15.2cm.

It´s a particularly active species and a group would need a tank measuring a bare minimum of 48" x 12" x 12"/120cm x 30cm x 30cm/108 litres, preferably larger.

Fairly undemanding provided its tank is well-maintained. It can appear a little washed out in very sparsely decorated set-ups though. A combination of good lighting and a darkish substrate will encourage it to show its best colours. Being a predominantly riverine species it does best in very clean, well-oxygenated water with a degree of flow and can look quite superb in a set-up decorated with smooth rocks, twisted roots and live plants. .

68 - 76°F/20 - 25°C

6.0 - 7.0

2 - 15°H

Like many barbs it's a generalised omnivore in nature feeding on a variety of worms, insects, crustaceans, plant matter and other organic debris. In the aquarium it's just as easily-fed and will greedily accept just about anything offered. For the best condition and colours offer regular meals of small live and frozen foods such as bloodworm, Daphnia and Artemia along with good quality dried flakes and granules.

This species makes an ideal addition to a peaceful community of slightly bigger southeast Asian species such as other similarly sized Puntius, larger rasboras and danionins and botiine loaches. If geography is not an issue it can actually be combined with most peaceful fish of a size too large to be considered food and that have a bold enough disposition to not be intimidated by its size and active nature.

It's a schooling species and really should be kept in a group of at least 8-10 specimens. Maintaining it in decent numbers will not only make the fish less skittish but will result in a more effective, natural looking display. The interaction between rival males can be quite superb at times. Any aggressive behaviour will normally also be contained as the fish concentrate on maintaining their hierarchical position within the group.

Tricky to sex when juvenile but as an adult the male is the more colourful sex and develops extended filaments to the dorsal fin rays. Mature females tend to be noticeably more rounded in the belly compared to males.

You'll need to set up a separate tank in which to spawn this species if you want to raise any numbers of fry. Something around 36" x 12" x 12" in size is usually recommended. This should be very dimly lit and contain clumps of fine leaved plants such as Java moss or Myriophyllum (spawning mops could also be used) to give the fish somewhere to deposit their eggs. Alternatively you could cover the base of the tank with some kind of mesh. This should be of a large enough grade so that the eggs can fall through it but small enough so that the adults cannot reach them. The water should be of around neutral pH, gH <8, with a temperature of around 75 - 80°F. A small air-powered sponge filter bubbling away very gently is all that is needed in terms of filtration.

Related species can be spawned in a group with half a dozen specimens of each sex being a good number. Condition these with plenty of small live foods and spawning should not present too many problems. Depending on your set-up simply check the spawning medium or tank base each morning for eggs.

Alternatively try spawning it in pairs. Under this technique the fish are conditioned in male and female groups in separate tanks. When the females are noticeably full of eggs and the males are displaying their best colours select the fattest looking female and best coloured male and transfer them to the spawning tank in the evening. They should spawn the following morning. Be sure to provide plenty of cover for the female as the male may be quite aggressive in his pursuit of her. In some cases she may even require a period of rehabilitation in a tank that does not contain any males.

In either situation the adults will probably eat the eggs given the chance and should be removed as soon as any are noticed. These should hatch in 24 - 48 hours with the fry becoming free swimming 24 hours later. They should be fed on an infusoria-type food for the first few days until they are large enough to accept microworm or Artemia nauplii.

This stunning species is also seen on sale labelled as "Blackspot Barb" on occasion and like some congeners has also been been imported under the names Puntius mahecola  or "Mahecola barb" in recent years. It lends it name to the Puntius filamentosus "group"; an assemblage of similar-looking species that currently contains P. arulius , P. assimilis , P. exclamatio, Puntius filamentosus, P. singhala, P. srilankensis and P. tambraparniei . The true identities of some of these species had been confusing to both hobbyists and scientists for many years until a revision was conducted by Maurice Kottlelat and Rohan Pethiyagoda in 2005. In the resulting paper the distinguishing features of Puntius filamentosus were given as follows:

"Adults of Puntius filamentosus are distinguished from all other South Asian Puntius by a combination of the following characters: branched dorsal-fin rays prolonged into filament-like extensions (in adult males only); a black band about as wide as the eye near tip of each caudal-fin lobe; lower lip continuous; a caudal blotch on 2-5 scales, commencing posterior to anal-fin origin; no distinct markings on body in advance of anal-fin origin. Additionally, Puntius filamentosus is distinguished from P. assimilis  by having a subterminal mouth (vs. inferior); maxillary barbels shorter, 0.5-2.2% of SL (vs. 5.5-9.3%); post-orbital head length 11.0-12.1% of SL (vs. 8.7-10.4%); and interorbital width 11.2-12.2% of SL (vs. 10.0-11.1%)."

The genus Puntius is currently viewed as something of a catch-all for well over 100 species of small cyprinid. Most experts agree that a full revision is required with the likely outcome that many species will be placed into new or different genera. When describing the genus in 1822 Hamilton identified the defining characteristics as: "absence or presence of maxillary only or rostral and maxillary barbels; dorsal fin with last simple ray serrate or entire, branched rays usually 8; anal fin with last simple ray entire, branched rays usually 5; lateral line complete or incomplete, lateral-line scales 17-36 in row; cephalic cutaneous papillae minute or absent; pharyngeal teeth in 3 rows, usually 2,3,5/5,3,2; colour pattern extremely variable." All the species currently in the genus are native to Southeast Asia, India and Sri Lanka.

The other main source of confusion with Puntius is that some authors do not recognise all the member species as such, rather following Walter Rainboth (1996) and preferring to place some into the alternative genus Systomus. Rainboth proposed that Systomus should be reinstated (it was first erected in the 19th century) as a valid genus on account of the fact that in its current state Puntius would seem to constitute a polyphyletic grouping i.e. not all of its members appear to have descended from the same common ancestor. The defining characteristics of a Systomus species are (according to Rainboth) a serrated (vs. smooth in Puntius) dorsal spine, the presence of 2 or 4 barbels (vs. always 2) and less than 12 gill rakers (vs. 12-20). SF tentatively lists all species as Puntius at present.

Literature cited

1. Pethiyagoda, R. and M. Kottelat. - Raffles Bull. Zool. Suppl. 12:127-144. 2005
   A review of the barbs of the Puntius filamentosus group (Teleostei: Cyprinidae) of southern India and Sri Lanka.
2. Pethiyagoda, R. and M. Kottelat. - Raffles Bull. Zool. Suppl. 12:145-152. 2005
   The identity of the south Indian barb Puntius mahecola (Teleostei: Cyprinidae).
3. www.petfrd.com
4. www.fishbase.org