This species has been in the aquarium trade since the early 1970s but its precise origin was a mystery until 2003.
It first appeared in Ukraine, the common name 'Odessa' being derived from the port city of that name, and when it arrived in western Europe was widely considered a hybrid of similar-looking congeners such as P. conchonius, P. ticto and P. cumingii.
It was also hypothesised as a subspecies of P. ticto or P. conchonius, and some suggested the fish to be artificially dyed.
Following the discovery of natural populations wild-caught specimens began to appear in the hobby and it became clear that the Odessa barb was a species in its own right but confusion continued for a further 5 years until the formal description was published in October 2008.
One interesting fact regarding the wild vs. aquarium strain of P. padamya is that the farm-produced fish seem to hold their colouration better when stressed.
Although this has yet to be verified we suspect that the original captive population of the species has been line-bred for colour over the years resulting in this trait.
In all other aspects both natural and ornamental variants appear identical.
P. padamya 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. phutunio, P. punctatus, P. reval, 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.
P. padamya can be told apart from congeners by the following combination of characters: presence of maxillary barbels; lateral line incomplete with 5-8 pored scales; 12 circumpeduncular scales; in adult males dorsal, anal and pelvic fins hyaline with black margins and 2-3 rows of black spots; humeral marking elongate vertically covering three or more scales; caudal peduncle marking covering parts of 1-2 scales, indistinct in adult males.
It's most similar to P. didi but can be told apart by the extent of the humeral marking which extends down to the lateral line (vs. reaching pectoral-fin base in P. didi), posession of dark margins and multiple rows of spots in the pelvic and anal fins (vs. lacking dark markings or with blackish marginal stripe and single row of spots across centre), and presence of orange-red flank pigmentation in males (vs. absence).
P. meingangbii and P. manipurensis share a colour pattern in which males possess red pigmentation on the flanks and caudal-fin.
The former is poorly-known but is supposed to lack barbels, have a larger marking on the caudal peduncle, and possess dark-to-reddish pelvic and anal fins, while in P. manipurensis the humeral marking is relatively small, barbels absent, and there are no dark spots in the pelvic and anal fins.
The genus Puntius was viewed as a polyphyletic catch-all containing over 100 species of small to mid-sized cyprinid for a number of years 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.
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