Butterfish

Diagnosis: posterior (=inner) side of pectoral-fin spines strongly denticulate; 58-68 branched anal-fin rays; 16-18 gill rakers on lower limb of first gill arch; barbels very short, nasal barbel extending to hind margin of eye; adipose fin always present; swim bladder extending backwards through a caecal appendix to above end of anal-fin base (Ref. 43912, 57127). Palatine teeth present (Ref. 57127). Posterior nostrils closer to each other than are anterior ones; 7-9 branched pelvic fin rays (Ref. 43912). Description: 12- 14 branched pectoral fin rays; 58-68 branched anal fin rays, the first 4-5 rays simple; pelvic fins with i+8 soft rays; 55-57 non-fused vertebrae; 9-12 branchiostegal rays on one side of head; caudal peduncle longer than deep; nasal barbels rather short, not reaching beyond orbit; maxillary barbel reaching at maximum to anterior border of opercle; outer mandibular barbel short and not reaching beyond posterior border of eye; inner mandibular barbels very short, rudimentary or sometimes absent; head rounded and rather narrow; lower jaw reaching anteriorly as far as snout or somewhat further (Ref. 43912). Probably most closely related to I. orientalis from the Juba-Uebi Shebeli system, from which it can be distinguished by the coarsely serrated inner side of the pectoral spine (Ref. 43912).Coloration: no observations on colour pattern in life (Ref. 57127). Preserved specimens: sides and belly pale and silvery, back and head darker; dorsal and caudal fins, as well as pectorals, lightly spotted; anal fin and pelvics unpigmented (Ref. 43912, 57127).

Distinct pairing (Ref. 205).

Dorsal spines (total): 1; Dorsal soft rays (total): - 6; Analsoft rays: 58 - 68

Probably carnivorous, feeding at least partly on small crustaceans (Ref. 43912). Oviparous, eggs are unguarded (Ref. 205).

fisheries:

Irvineia voltae is a species of schilbid catfish endemic to the lower Volta River in Ghana. This species grows to a length of 17.8 centimetres (7.0 in) SL. They are oviparous and do not guard their eggs.