Cá Phèn rưng

Diagnosis. Dorsal fins VIII + 9; pectoral fins 15 – 17; gill rakers 5 – 7 + 2 0 – 23 = 26 – 29; measurements in % SL, large-sized fish: body depth at first dorsal-fin origin 29 – 35; body depth at anus 23 – 29; caudal-peduncle depth 10 – 12; maximum head depth 26 – 31; head depth through eye 21 – 25; interorbital length 7.7 – 9.2; head length 31 – 34; snout length 14 – 17; postorbital length 10 – 13; orbit length 5.8 – 8.1; upper jaw length 12 – 14; barbel length 25 – 29; caudal-peduncle length 21 – 25; caudal-fin length 29 – 33; anal-fin height 13 – 16; pelvic-fin length 22 – 25; pectoralfin length 23 – 28; first dorsal-fin height 20 – 23; second dorsal-fin height 11 – 15; small-sized fish: body depth at first dorsal-fin origin 28 – 30; body depth at anus 23 – 26; caudal-peduncle depth 10 – 11; maximum head depth 24 – 27; head depth through eye 19 – 22; interorbital length 7.7 – 8.4; head length 30 – 34; snout length 13 – 15; postorbital length 10 – 13; orbit length 6.6 – 8.3; upper jaw length 12 – 13; barbel length 26 – 28; caudal-peduncle length 22 – 25; caudal-fin length 29 – 32; anal-fin height 14 – 16; pelvic-fin length 23 – 24; pectoral-fin length 24 – 26; first dorsal-fin height 19 – 21; second dorsal-fin height 13 – 15; maxilla posterior margin evenly, symmetrically rounded; body and head purple red or vermillion, colour may become paler below lateral line and eye; scale edges darker; scales often with pale violet or pearly iridescent spot; body silvery white ventrally; one or two indistinct narrow yellow-orange stripes sometimes visible, one of them just above or along lateral line and more conspicuous, the other further below; a small dark red or reddish-brown spot on or just below the eighth lateral-line scale in both large- and smallsized fish; caudal fin red at base and ventrally of lower lobe, the remaining parts yellowish to pale orange; dorsal and anterior parts of anal and pelvic fins red or orange; barbels white or pale orange except for the white