Diagnosis: Nothobranchius capriviensis is known only as blue form, in contrast to N. kafuensis, its closest relative, that occurs as red, blue and intermediate forms; while there are general similarities in male colouration between N. capriviensis and the blue form of N. kafuensis, there are also consistent differences: the male N. capriviensis can be distinguished by the paler shade of blue than the blue phenotype of N. kafuensis, the lack of orange-red scale margins and the orange-red colour on the head of the latter species, and a more prominent and consistent barring on the body of the former; differences in female colouration are not as obvious: scale centers of N. capriviensis are iridescent light blue, whereas those of female N. kafuensis are less prominently blue and have a silver hue (Ref. 116076). Morphologically and meristically, the male N. capriviensis differs from that of N. kafuensis by a deeper body, its mean 35.4% of standard length vs. 31.4%, longer head, its mean 32.5% of standard length vs. 30.7%, a more posterior position of the anal fin, pre-anal length 62.3% of standard length vs. 60.5%, and a higher number of scales around the caudal peduncle, 14-16 vs. 13-14; female N. capriviensis have a more posterior position of the anal fin, pre-anal length 63.9% of standard length vs. 66.8%, when compared with N. kafuensis

Description: This is a Nothobranchius species of moderate size with a pointed snout and subterminal mouth directed slightly upward; the head profile is slightly convex, to concave in older males, with no distinct transition to the dorsal profile; the dorsal profile is convex from the nape to the dorsal fin base; the caudal peduncle profile is slightly concave at the upper and lower sides (Ref. 116076). The supra-orbital squamation is variable, but most specimens have G-type, partly covered with epidermal tissue anteriorly; the central supra-orbital neuromast systems are in two distinct shallow grooves, both sides of each lined with three shallow lobes; the posterior cephalic neuromast systems are in two curved pits; scales in the median longitudinal line number 28-31, plus 1-3 on the caudal fin base, most with a shallow pit in the center and one neuromast; the transverse rows of scales above the pelvic fins number 12-14, and the scale count around the caudal peduncle is 14-16 (Ref. 116076). The dorsal fin rays number 15-18, the anal fin rays 16-18, and the position of the base of the first anal fin ray is under the base of dorsal fin ray 1 or 2; the pelvic fins are short, not reaching the first anal fin ray; the pectoral fins reach the first pelvic fin ray (Ref. 116076).

Colouration: For live males of the Sakamanduna population, the body is light blue-gray with a brilliant blue-green iridescence, the abdomen white and the back gray-brown with a distinct yellow to golden hue; the posterior margins of most scales are pale gray to golden-yellow, the latterbeing a more prominent feature on the scales of the upper sides; the golden-yellow scale margin colour becomes more extensively developed on the back resulting in an overall yellow-golden hue; the sides show a variable number of rearward-pointing, commonly irregular, chevron-shaped cross-bars of variable height, width and spacing; in general, these cross-bars are formed by dark red-brown to maroon scale margins; in some specimens the cross-bars may, in part, be arranged in pairs, producing a generally coarser pattern; the throat is pale blue-gray with no markings present; two or three oblique bars, of the same colour as the bars on the body, are present on the operculum; the projecting part of opercular membrane is light gray with a white margin (Ref. 116076). The basal half of the caudal fin is light blue-gray to blue-green with a golden hue and irregularly dispersed dark red-brown to marron spots; this component is followed distally by a dark red-brown or maroon band, a wider light blue submarginal band and a narrow black margin; the blue submarginal band may include some pale yellow flashes; the dorsal fin is light blue-gray to yellow-gray with irregular, dark brown to maroon stripes and spots which become denser and smaller distally; the base of the dorsal fin usually shows five to seven distinct, relatively large and angular, dark brown to maroon markings; most specimens show a concentration of a few small black markings along the anterior marginal part of the dorsal fin; the proximal part of the anal fin is light blue-gray to yellow-gray with some dark red-brown to maroon spots; this zone is followed by an irregular, and commonly interrupted, dark red-brown to maroon band; the broad outer part of the fin, comprising approximately one-third, is usually light blue with yellow overtones; in some specimens the yellow colour is strongly developed and may be the dominant colour in this part of the fin; a narrow black margin may be present; the pelvic fins have a colour pattern similar to that of the anal fin although the dark red-brown to maroon spots may be absent; the pectoral fins are hyaline with pale blue or blue and yellow posterior margins; the iris is golden-brown with a golden ring around the pupil and a vertical black bar (Ref. 116076). Males of the Salambala population have in general a similar colour pattern, but the development of golden-yellow scale margins on the body is somewhat more prominent and in some specimens extending from the back to the lower flanks; there is also a greater tendency for cross-bars on the body to be arranged in pairs, producing a generally coarser pattern; a yellow colour in the outer part of the anal fin is more common in males of this population (Ref. 116076). For live females, the body is pale gray-brown, darker on the back, grading to white on the abdomen; scales on the back and upper sides have reflective light blue centers and narrow gray-brown margins, producing a faint reticulated pattern; faint, narrow cross-bars may occur on the rear part of body, produced by a local widening of scale margins; both the paired and unpaired fins are colourless; the iris is pale golden with an indistinct, relatively dark vertical bar (Ref. 116076).