Morphology Data of Nothobranchius rachovii
Identification keys
Main Ref. Shidlovskiy, K.M., B.R. Watters and R.H. Wildekamp, 2010
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks Males: body laterally compressed and deep; all unpaired fins rounded, dorsal and anal fin covered with epidermal tissue; papillae on all dorsal and anal fin rays, projecting from epidermis; tips of dorsal and anal fin rays not projecting from fin membrane; opercular membrane projecting from opercle, distal edge slightly wrinkled (Ref. 85866). Females: smaller than male; body less deep than in male, depth 22.8-32.1% of standard length vs. 25.5-33.8%; dorsal and caudal fins rounded, anal fin triangular, tip rounded, rays 3-8 longer and more rigid; anal fin positioned more posteriorly than in male, pre-anal length 62.8-67.9% of standard length vs. 58.4-65.7%; no epidermal tissue covering dorsal and anal fins or papillae on rays; opercular membrane not projecting from opercle (Ref. 85866).

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth superior
Type of scales

Diagnosis: Nothobranchius rachovii is distinguished from other species of the genus by the following combination of characters: in males, a bright colouration consisting of alternating light blue and orange-red bars on the body and fins, orange-red head, and orange subterminal and black terminal bands in the caudal fin (Ref. 85866). It can be distinguished from the other species of the subgenus Nothobranchius as follows: from N. furzeri by male colouration, higher number of dorsal fin rays, 15-17 vs. 14-15, and a lower number of scales on the mid-longitudinal series, 26-28 vs. 28-30; from N. orthonotus by male colouration, lower number of scales on the mid-longitudinal series, 26-28 vs. 28-33, and shape of the dorsal profile, convex vs. flat; and from N. kadleci by male colouration and shape of the frontal region, higher number of dorsal and anal fin rays, 15-17 vs. 13-14 and 15-17 vs. 13-14 (Ref. 85866). Females can be distinguished by the presence of a reflective light blue spot on all scales of the flanks, vs. few, irregularly dispersed light blue-green spots in N. furzeri and N. kadleci or frequent presence of brown spots on body and fins in N. orthonotus (Ref. 85866). Nothobranchius rachovii can also be distinguished from all other species of the genus by its low number of diploid chromosomes, 2n=16 (Ref. 85866).

Description: A robust Nothobranchius species of medium size; snout pointed, mouth terminal, slightly directed upward; body laterally compressed and deep; dorsal profile slightly concave on head, convex from nape to end of dorsal fin; in older males more convex than in younger specimens; upper and lower profiles of caudal peduncle nearly straight (Ref. 85866). Supra-orbital squamation of G-type; frontal part of supraorbital squamation partly covered with epidermal tissue; frontal and central supraorbital neuromast systems, on top of the head, fused and forming two distinct shallow grooves; both lined with three shallow lobes at both sides of the groove; posterior cephalic neuromast systems in two curved pits (Ref. 85866). Dorsal fin rays 15-17, anal fin rays 15-18, relative position of base of first dorsal-fin ray over base of second or third anal-fin ray; pelvic fins short, not reaching origin of anal fin; pectoral fins reaching to origin of pelvic fins (Ref. 85866). Scales on the median longitudinal line 26-28 plus 2-3 on caudal fin base, most with a shallow pit in centre; transverse row of scales above pelvic fins 11-12, circumpeduncular scales 12-13 (Ref. 85866).

Colouration: Live male: general body colour iridescent light blue to pale blue-green or blue- grey, variable according to population; head and throat orange, grading across operculum into light blue of body; posterior margin of scales orange-red to brown-red, giving a strong reticulated appearance; locally, scale margins are wider and merge to form chevron-shaped cross-bars, apex rearward; dorsal and anal fins pale blue to light blue-grey, distally with orange-red to red-brown spots and stripes; dorsal fin with narrow blue-white margin; caudal fin pale blue to blue-grey with orange-red to red-brown spots and bars in the basal half, followed by a brown band grading into a wide orange subterminal band; caudal fin margin black; ventral fins light blue with some small red proximal spots; pectoral fins pale translucent orange with light blue margin; iris golden with dark vertical bar (Ref. 85866). Live female: body colour olive grey-brown, frontal scales on flanks with iridescent light blue to silvery centers; all fins colourless; iris bronze to golden with dark vertical bar (Ref. 85866).

Ease of Identification

Meristic characteristics of Nothobranchius rachovii

Lateral Lines Interrupted: No
Scales on lateral line 28 - 31
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle 12 - 13
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total 0 - 0
Soft-rays total 15 - 17
Adipose fin absent

Caudal fin

Attributes more or less truncate; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 15 - 18

Paired fins

Pectoral Attributes  more or less normal
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Comments & Corrections
Back to Search
cfm script by eagbayani, 17.10.00, php script by rolavides, 13/03/08 ,  last modified by sortiz, 06.27.17