Family Cyprinidae

1. 1. Lateral line complete

      Go to 2
   2. Lateral line incomplete

      Go to 3
2. 1. Present of barbels

      Go to 4
   2. Absent of barbels

      Go to 5
3. 1. Nature of dorsal fin spines – Serrate

      Go to 6
   2. Nature of dorsal fin spines – Smooth

      Puntius titteya
4. 1. Two pair of barbels present

      Go to 7
   2. Single pair of barbels present

      Labeo Lankae
5. 1. Position of mouth- Subterminal

      Go to 8
   2. Position of mouth- Terminal

      Rasbora wilpita
6. 1. Present of bands on the body

      Go to 9
   2. Absent of bands on the body

      Rasboroides vaterifloris
7. 1. Presence of 8–9 dark, irregular bars on body

      Devario pathirana
   2. Not presenting of 8–9 dark, irregular bars on body

      Go to 10
8. 1. Nature of dorsal fin spines- Serrate

      Pethiya nigrofasciata
   2. Nature of dorsal fin spines- Smooth

      Dawkinsia srilankensis
9. 1. Pelvic, anal and dorsal fins are tinted with yellow

      Pethiya cumingi
   2. Pelvic, anal and dorsal fins are tinted with black

      Pethiya Bandula
10. 1. Consist of black strips, running on the lateral side along the body

       Go to 11
    2. No black strips, running on the lateral side along the body

       Labeo fisheri
11. 1. Position of mouth- Sub Terminal

       Systomus asoka
    2. Position of mouth- Terminal

       Systomus martenstyni

Family Cobitidae

1. Scales on top of head absent; presence rows of 3-6 broad, regularly-spaced dark bars on caudal-fin; a dark stripe from eye to upper lips and vertically elongated black blotch on the base of caudal fin

   Lepidocephalichthys jonklaasi

Family Gobiidae

1. 1. Body naked

      Schismatogobius deraniyagalai
   2. Body covered with scales

      Go to 2
2. 1. Have bright red colored elliptical blotched in the base of the caudal fin

      Sicyopus jonklaasi
   2. No bright red colored elliptical blotched in the base of the caudal fin

      Sicyopterus halei

Family Osphronemidae

1. 1. Have two dark lines which start from snout to posterior end of the operculum

      Malpulutta kretseri
   2. No dark lines present on the body

      Belontia signata

Family Claridae

1. Mouth terminal; 4 pairs of barbels; dorsal fin inserted the slightly anterior tip of pectoral fins; body naked; dorsal fin inserted the slightly anterior tip of pectoral fins; pectoral spine strong and fairly serrated on both edges

   Clarias brachysoma

Family Mastacembelidae

1. A line starting from the tip of the snout to the base of the caudal fin present above the lateral line; have separated dorsal, caudal and anal fins, 14-16 dorsal spines are present; 24 pairs of rostral tooth plates; pre-dorsal length of 43.3-46.8% SL

   Macrognathus pentophthalmos

Family Channidae

1. Pelvic fins are absent, Body elongate and fairly rounded in cross-section, Color of the dorsal side flanks greenish, lateral side pale with a faint brown with a blue tint, Dorsal and anal fins are bluish-green and edges white, Membrane of pectoral fins transparent with dark brown rays, sclera bright orange

   Channa orientalis