Diagnosis: Fenerbahce devosi shares the following combination of characters with F. formosus: small species with maximum total length below 4 cm, reflective scales dorsally on the head, complete absence of tubular structures in the pre-, post-, supraorbital, and opercular neuromast system, and small dorsal fin (Ref. 87349). All Fenerbahce specimens can be divided by the combination of several morphological characters into two clades: the western clade includes the populations from Voula to the Tshuapa River, the eastern clade the populations from the Aruwimi River to Nikambwe and Epulu; the western clade differs from the eastern clade by a more posterior insertion of the dorsal fin in relation to the anal fin, D/A=1/10–14 vs. D/A=1/7–10; a slightly lower number of vertebrae, 25–26, except in F. sp. ‘Tshuapa' 28–29, vs. 27–30; a fused hypural fan or both hypural plates only on posterior 20% not fused vs. both hypural plates not or only on anterior half fused; a mean lower number of caudal fin rays attached to hypural plates or fan, 8–9 vs. 9–10 (Ref. 87349). Fenerbahce devosi is distinguished from F. formosus by the combination of the following characters: a more robust species; observed maximum total length larger, largest observed male, kept in an aquarium, approximately 38 mm total length, not preserved, largest value given for F. formosus is 30 mm; dorsal fin inserts in a more anterior position compared to the anal fin, D/A=1/8–9, vs. a more posterior inserted dorsal fin in F. formosus, D/A=1/10–14; Fenerbahce devosi has a deeper body then F. formosus, body depth as percentage of standard length ranges from 21.7–23.2 in F. devosi and from 17.9–21.2 in F. formosus; extensions of the edges of caudal fin can be almost as long as the fin itself in adult males, in F. formosus caudal fin extensions are only half the length of the caudal fin (Ref. 87349). Body colour of males on sides yellow-green to blue-green, unpaired fins in centre blue-green to greenish vs. body pale-blue to silvery and centre of unpaired fins light blue in F. formosus (Ref. 87349). Anal fin orange to yellow-greenish, with a row of red dots at anal base and vague orange edge in F. devosi vs. pale blue with basal red stripe and discrete red edge in F. formosus; southern populations of F. formosus with red spots and/or stripes in middle section of anal fin; lower half of caudal fin orange to yellow-greenish vs. pale blue in F. formosus; dorsal fin spotted at base in F. devosi vs. a red basal stripe and complete fin spotted with inter radial red stripes in F. formosus; caudal fin spotted without inter radial red stripes in F. devosi vs. spotted with inter radial red stripes in F. formosus; pelvic fin like anal fin, yellow to blue-green with red border in F. devosi vs. pale blue with red border in F. formosus; pectoral fin in males transparent with an orange or yellow hue and small blue border vs. transparent with a light blue distal edge (Ref. 87349). Fenerbahce devosi is distinguished from F. sp. ‘Epulu’, F. sp. ‘East Congo’ and F. sp. ‘Tshuapa’ by a deeper body and a shorter head, and from F. sp. aff.devosi by some small differences in measurements and male colouration (Ref. 87349).

Description: Small nothobranchiid species, largest observed specimen in the type series 31.1 mm total length (Ref. 87349). Dorsal profile straight or slightly convex, greatest body depth at base of pelvic fin, ventral profile slightly convex; snout rounded, mouth directed upwards, lower jaw longer than upper jaw, posterior end of rictus at level of dorsal third of eye (Ref. 87349). Frontal neuromasts in two separate grovves, pre-, post-, and supraorbital neuromast system and upper two pit organs of the preopercular neuromast system lack tubular structures; two supraorbital grooves with three neuromasts each; anterior most neuromasts of supraorbital system in line with frontal neuromasts; all neuromasts are situated in more or less shallow grooves or simply on top of the skin (Ref. 87349). Teeth on jaws unicuspid, outer row large and curved, inner teeth smaller and more irregularly placed; considerable variation in width of vomer and parasphenoid (Ref. 87349). Total number of vertebrae 27-28; the hypurals 1 & 2 and 3-5 are fused in two hypural plates, both hypural plates in anterior half fused; ten caudal fin rays attached to hypural plates (Ref. 87349). Scales cycloid, body completely scaled except ventral head surface; frontal squamation of G-type; typical for the genus are the silvery scales on top of the head just behind the level of eyes; no scales on dorsal and anal fin base; two or three scale rows on caudal fin base; scales on mid longitudinal series 26-30, transverse series of scales before dorsal fin 9, 12 circumpeduncular scale rows (Ref. 87349). All unpaired fins pointed in males, older males show elongated rays at the caudal fin edges; number of dorsal fin rays 8-10, anal fin rays 14-16; first dorsal fin ray above anal fin ray 8-9; fins in females smaller and rounded; pectoral fin not or just reaching pelvic fin (Ref. 87349).

Colouration: Live colouration in males: side of body yellow- to blue-green, metallic copper dorsally; most scales on side with a red spot forming up to seven horizontal lines; these are sometimes interrupted, especially the anterior part of the lower lines; dorsal side copper to brown coloured, ventral from chin to pelvic fin pale whitish; on head just posterior of eyes metallic silvery scales; three red streaks on opercle in an approximate 45° angle, lower red streak behind the eye reduced to a red spot; dorsal fin green-blue to blue with more or less complete dark red margin; red spots between fin rays at the fin base; anterior part of dorsal fin only with spots at the base, posterior part with small red spots or short streaks; anal fin yellow- to blue-green with orange distal part and red-orange margin; a row of red spots at the fin base; upper half of caudal fin blue-green, lower half yellow to orange, centre greenish; caudal fin with red spots especially in the centre of the fin, fusing to small streaks in posterior part; all caudal fin edges with red margin, fin extensions yellow; pectoral fin hyaline with orange hue; pelvic fin yellow to orange with dark red margin (Ref. 87349). Livecolouration of females: body light brown to grey-brownish, dorsally darker and ventrally light brown; scales on sides with a dark border, forming a reticulated pattern; most scales on dorsal half of sides with a small red dot; all fins hyaline, only some scattered red dots (Ref. 87349).