Pethia reval

Pethia: the generic vernacular name for small cyprinids in the Sinhala language.

reval: from the conjunction of the Sinhala root for red (re) and noun for fins (val, varal), alluding to the distinctive color of the fins of this species.

Endemic to western Sri Lanka where it's known from the Kelani and Maha Oya river systems plus smaller drainages which lie between them such as the Attanagalu and Kalu rivers.

In the south of this range a natural hybrid between P. cumingii and P. reval may occur, while a population inhabiting the Mahaweli River, which drains into the Bay of Bengal in the northeast of the island, appears to have been introduced artificially.

Type locality is given as 'Kelani River basin, Labugama (near Hanwella), 6°51'N, 80°10'E, Sri Lanka, elevation 90 meters.'

No details are provided in its description, but this species presumably inhabits smaller tributary drainages rather than main river channels.

Base dimensions of at least 75 ∗ 30 cm30 ∗ 12 in or equivalent are required.

Choice of décor is not especially critical though it tends to show better colouration in a heavily-planted set-up with a dark substrate.

The addition of some floating plants and driftwood roots or branches to diffuse the light entering the tank also seems to be appreciated and adds a more natural feel.

Filtration does not need to be particularly strong though it does seem to appreciate a degree of water movement and will also do well in a hill stream-type set-up.

Wild fish are probably foragers feeding on diatoms, algae, organic detritus, small insects, worms, crustaceans, and other zooplankton.

In the aquarium it's easily-fed but the best condition and colours offer regular meals of small live and frozen foods such as bloodworm, Daphnia, and Artemia, alongside good quality dried flakes and granules, at least some of which should include additional plant or algal content.

Generally very peaceful making it an ideal resident of the well-researched community aquarium.

As it places no special demands in terms of water chemistry it can be combined with many of the most popular fish in the hobby including other small cyprinids as well as tetras, livebearers, rainbowfishes, anabantoids, catfishes, and loaches.

It's a schooling species by nature meaning at least 6-10 specimens should be purchased.

Maintaining it in such numbers will not only make the fish less skittish but result in a more effective, natural looking display, plus males will develop better colours in the presence of conspecific rivals.

Adult males are noticeably smaller, slimmer, and more intensely-coloured than females, especially when in spawning condition.

Unrecorded.

This species was considered a colour form of the related Pethia cumingii prior to its description.

It can be told apart from P. cumingii by the following combination of characters: maximum standard length 33.6 mm (vs. 41.2 mm1.6 in); smaller eye diameter (9.8-10.5, vs. 10.8-12.1 % SL); 11+13 (vs. 11+15) vertebrae; cleithrum with a single spine (vs. smooth); proximal arm of fifth ceratobranchial with an oval foramen of diameter less than (vs. greater than) basal diameter of teeth; red, (vs. yellow) finnage.

P. reval was formerly included in the Puntius conchonius 'group' of closely-related species alongside P. ater, P. bandula, P. conchonius, P. cumingii, P. didi, P. erythromycter, P. gelius, P. khugae, P. macrogramma, P. manipurensis, P. meingangbii, P. nankyweensis, P. nigripinnis, P. nigrofasciatus, P. padamya, P. phutunio, P. punctatus, P. shalynius, P. stoliczkanus, P. thelys, P. tiantian, and P. ticto, but all of these were moved to the new genus Pethia by Pethiyagoda et al. (2012) as were P. melanomaculata, P. pookodensis, P. muvattupuzhaensis, P. ornatus, and P. yuensis.

‘Puntius‘ narayani was not moved to the new genus and is currently of uncertain generic placement since it uniquely possesses 9 branched dorsal-fin rays and 6 branched anal-fin rays.

Pethia species are defined by the following combination of characters: rostral barbels absent; maxillary barbels minute or absent; possession of a stiff, serrated last unbranched dorsal-fin ray; presence of a black blotch on the caudal peduncle, and frequently, black blotches, spots or bars on the side of the body; infraorbital 3 deep and partially overlapping the preoperculum.

In P. cumingii the flank markings comprise two black, vertically-orientated blotches, one posterior to the operculum and the other on the caudal peduncle, and this patterning is shared with the congeners P. bandula, P. didi, P. meingangbii, P. padamya, P. phutunio, and P. tiantian.

P. reval is distingushed from these by its red fin colouration plus the following combination of characters: barbels absent; last unbranched dorsal ray serrated; lateral line incomplete, perforating 4-9 scales; scale rows above lateral line arranged in a distinctive pattern; dorsal, anal and pelvic fins red (pale yellow in the Kalu River population); body colour pattern consisting of two black bars, one behind gill opening and one above posterior extremity of anal-fin base; dorsal, anal and pelvic fins red.

The genus Puntius was for a number of years viewed as a polyphyletic catch-all containing over 100 species of small to mid-sized cyprinid until Pethiyagoda et al. (2012) published a partial review covering South Asian members.

The majority of sub-Himalayan Puntius species were reclassified and new genera Dawkinsia, Dravidia, and Pethia erected to accomodate some of them, with the remainder either retained in Puntius or moved to the existing Systomus assemblage, though the definition of the latter was altered meaning some Southeast Asian species formerly placed there are no longer members.

It subsequently became clear that the name Dravidia was preoccupied by a genus of flesh fly, therefore the replacement name Haludaria was made available by Pethiyagoda (2013).

No species from Indochina, China, or Indonesia were included in the study meaning a significant number of former Puntius are currently classed as incertae sedis, i.e., of uncertain taxonomic placement, and this also applies to a number of South Asian species of unresolved status.

They’re perhaps best referred to as ‘Puntius‘ for the time being whereby the genus name is surrounded by quotation marks to denote its questionable usage, and that is the convention used here on SF at the moment.