Puntius assimilis - "Mahecola" Barb

Cyprinidae

Endemic to the Southwest Indian states of Karnataka and Kerala where it has been collected from the Nethravati, Chalakudy and Kallada river basins in recent years. The type locality in the original description of the species was simply given as "a river in Canara" (Canara being a region of Karnataka comprising several districts).

According to Pethiyagoda and Kottelat (2005) this species occurs in various habitat-types depending on the collection locality. In the River Nethravati it was found to inhabit marginal areas with sluggish flow and muddy substrates. In the Chalakudy it was collected from clear, rocky, "relatively fast-flowing" stretches that occur between the numerous waterfalls formed as the river descends from the Western Ghat mountain range. The Kallada fish were found in similar (clear water, rocky substrate) but slower-moving waters. The authors go on to hint that some or all of these populations may turn out to be distinct species following additional study but that they should be treated as conspecific "for the present".

Around 4.3"/11cm.

It´s a particularly active species and a group would need a tank measuring a bare minimum of 48" x 18" x 18"/120cm x 45cm x 45cm/255 litres.

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.

66 - 77°F/19 - 25°C

6.0 - 7.0

2 - 10°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.

It makes an ideal addition to a peaceful community of slightly bigger Southeast Asian species such as other similarly sized Puntius, rasboras, 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 by nature 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 in some populations exhibits extended filaments to the dorsal fin rays. Mature females tend to be noticeably more rounded in the belly.

Possibly not yet bred in the hobby but can probably be spawned in a similar way to other barbs in the P. filamentosus  group. You'll need to set up a separate tank in which to do so if you want to raise any numbers of fry. Something around 36" x 12" x 12" in size recommended. This should be very dimly lit and contain clumps of fine leaved plants such as Java moss, Myriophyllum, or alternatively spawning mops to give the fish somewhere to deposit their eggs. OR 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.

Puntius assimilis has for a number of years been imported and sold under the incorrect names Puntius mahecola  or "Mahecola barb". We use the latter trade name in this profile purely as a means of assisting in searching for the species within our knowledge base. The issue surrounding its true identity came to light in a 2005 revision of the P. filamentosus  'group' by Maurice Kottlelat and Rohan Pethiyagoda. This contains a handful of South Indian and Sri Lankan barb species that share similar morphological characteristics and currently contains P. arulius , Puntius assimilis, P. exclamatio, P. filamentosus , P. singhala, P. srilankensis and P. tambraparniei . The distinguishing features of Puntius assimilis were given as follows in the paper:

"Adults (> 43.3 mm SL) of Puntius assimilis are distinguished from all other South Asian Puntius by a combination of the following characters: a black band about as wide as eye across each caudal-fin lobe (faint or absent in adults of the Kallada River population); lower lip continuous, a caudal blotch on 2-5 scales, commencing posterior to anal-fin origin; no prominent markings on body in advance of anal-fin origin. In adult males of the Chalakudy and Kallada River populations, branched dorsal rays prolonged into filament-like extensions. Additionally, adult Puntius assimilis may be distinguished from P. filamentosus  by having mouth inferior (vs. subterminal) and maxillary barbels 23.5-33.3% HL (vs. 2.8-8.1%)."

Along with this revision paper the authors also published a second paper discussing the true identity of P. mahecola . They had studied the syntypes of the species as part of their research for the filamentosus group paper and discovered that whilst the name and description of P. mahecola  are valid it cannot even be considered to be closely related to P. filamentosus  or any of the species in this group. It is in fact a much smaller, silvery fish with a single dark blotch on the caudal peduncle that has been pictured in much of the available literature mislabelled as P. amphibius!

The name P. mahecola  had also previously been considered a synonym of P. filamentosus  by several authors but the mistake was exacerbated when a new filamentosus-type fish was discovered in the Chalakudy river in 1996 and exported under the false name P. mahecola  on a purely commercial basis. Pictures of this fish were subsequently used by a governmental agency to depict P. mahecola  on a poster showing images of native Indian species. As a result in the following years several species, including Puntius assimilis and P. filamentosus , have been imported and sold as P. mahecola  and it wasn't until the publication of the two papers discussed above that the truth became known. At time of writing P. filamentosus -type fish can still occasionally be seen on sale with the mahecola label and an inflated price tag attached.

As if all this isn't messy enough the identity of Puntius assimilis has not actually been resolved in full. Kottelat and Pethiyagoda suggest that some of the different populations of the fish may turn out to be distinct species in the future (the uncertaintly being due to insufficient numbers of adult specimens from the three localities being available for their study). In particular the form from the Kallada River is said to differ as it has much fainter black markings on the caudal fin. More recently an assimilis-like fish with a permanent mid-lateral body blotch has been seen in the trade. Intriguingly this one was collected in Kerala from the locality where P. exclamatio and Puntius assimilis are said to occur sympatrically. Perhaps further study on the filamentosus group of Puntius will reveal the assemblage to be more diverse than is currently recognised.

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