Puntius rhomboocellatus - Snakeskin Barb

Cyprinidae

This species is quite widely-distributed throughout Kalimantan (the Indonesian part of the island of Borneo) although judging by collection records it appears to be found only in more southerly parts of the territory. It has been recorded from several river systems including the Kapuas, Kepayang, Barito and Kahajan.

Usually inhabits peat swamps and associated blackwater streams. These ancient biotopes are mostly found in forested areas. The water is typically stained dark brown with humic acids and other chemicals released by decaying organic material. The dissolved mineral content is negligible, and the pH can be as low as 3.0 or 4.0. The dense rainforest canopy above means that very little light penetrates the water surface. The substrate is normally littered with fallen tree branches and rotting leaves.

Around 2"/5cm.

A tank measuring 18" x 15" x 12"/45cm x 37.5cm x 30cm/50 litres could comfortably house a group of these.

This species can be a little delicate at first and is best added to mature set-ups but is otherwise quite undemanding provided its tank is well-maintained. It can appear a little washed out in very sparsely decorated set-ups though. A combination of fairly dim lighting and a dark substrate will encourage it to show its best colours. It can look quite superb in a heavily planted setup decorated with pieces of bogwood, twisted roots and a layer of surface vegetation to create shade.

It will also do well in a tank set up to recreate a peat swamp-type environment with dim lighting, roots and branches, leaf litter and real peat fibre added to the filter or mixed into the substrate. You could also add Asian plant species that can survive under such conditions such as Microsorum pteropus (Java fern), Taxiphyllum barbieri (Java moss) and Cryptocorynes. Filtration should not be too turbulent as it hails from sluggish waters.

73 - 82°F/23 - 28°C

This species does best in acidic to neutral water within the range 5.0 - 7.0.

1 - 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.

IThis species makes an ideal addition to a peaceful community of Southeast Asian/Indian species such as other similarly-sized Puntius, rasboras, botiid/cobitid loaches and gouramis of the genus Trichogaster. In a biotope set-up you could try it alongside other Bornean blackwater species. There are many suitable choices but some of the more commonly exported ones include Puntius lineatus , P. pentazona , Rasbora dorsiocellata , R. pauciperforata , R. gracilis , Trigonostigma hengeli  and Pangio (kuhli) loaches.

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. Any aggressive behaviour (unlikely with this species) will usually be contained within the group as the males compete with each other for female attention and they will also display their best colours far more often. Unusually for a barb the female is reported to be the more boisterous fish.

Adult males tend to be slightly smaller, are noticeably slimmer and exhibit more intense colouration than females.

We've thus far been unable to get hold of any breeding reports for this species so suggest using the method for P. gelius  as a starting point, reproduced here.

You'll need to set up a separate tank in which to spawn the fish if you want to raise a decent number of fry. Something around 12" x 8" x 8"/30cm x 20cm x 20cm in size is fine. This should be dimly lit and contain clumps of fine-leaved plants such as java moss or spawning mops, 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 pH should be slightly on the acidic side of neutral. Set the temperature a few degrees higher than in the conditioning tank, as a raise in temperature is said to induce the fish to spawn. A small air-powered sponge filter bubbling away very gently is all that is needed in terms of filtration.

It's best spawned in pairs, conditioning the fish in a group in a separate tank. When the females are noticeably full of eggs and the males are displaying their best colours, select the fattest female and best-coloured male and transfer them to the spawning tank in the evening. They should spawn the following morning with the eggs being deposited among the plants.

The adults should be removed as soon as you spot the eggs as they will eat them given the opportunity. A magnifying glass can be useful here. They will hatch in 24-36 hours, with the fry becoming free swimming after 3-4 days. At this stage begin to offer small amounts of an infusoria-type food several times per day, until they are large enough to accept microworm or Artemia nauplii. Small daily water changes of 10-20% should also be performed until the fry are 3-4 months old, by which age they should be of saleable size.

This species is also commonly known as the "Rhomb/Rhombo" barb among hobbyists. It is superficially similar to several others in the genus most notably P. pentazona , P. hexazona and P. foerschi. So similar in appearance and behaviour are these that one school of thought proposes that they are simply regional variations of a single species (suggested to be Puntius pentazona ). The easiest way to distinguish them from one another is to examine the pattern of dark vertical bars and markings that adorn the flanks of the fish. The bars are characteristically split to form diamond-like shapes in Puntius rhomboocellatus whereas in the other species they are solid.

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 being somewhat variable: "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. Kottelat, M. and E. Widjanarti. - Raffles Bull. Zool. Supplement (13):139-173. 2005
   The fishes of Danau Sentarum National Park and the Kapuas Lakes area, Kalimantan Barat, Indonesia.
2. Kottelat, M. - Raffles Bull. Zool. 40(2):187-192. 1992
   The identity of Barbus johorensis Duncker, 1904 (Teleostei: Cyprinidae).
3. www.fishbase.org