Diagnosis: Salariopsis atlantica differs from other known species of Salariopsis by the following combination of characters: head without diagonal rows of black dots on the cheeks running backwards and downwards from the lower edge of the eye as in S. economidisi and S. fluviatilis; number of teeth 13-15 on upper jaw and 14-16 on lower; supra-temporal canal with 3 cephalic pores; pre-opercular canal with 7-9 cephalic pores; circum-orbital canal with 8-9 cephalic pores (Ref. 89850). Supra-ocular tentacle thick and simple; 16-17 branched rays in the anal fin vs. 16-19 in both S. fluviatilis and S. economidisi; short pre-orbital distance; short anterior region (spiny) of the dorsal fin; 34 vertebrae (Ref. 89850).

Description: A small species that rarely reaches 60 mm; maximum body depth is 21.7-24.7% of standard length in males and 19.6-21.1% of standard length in females; head is wider in males, head length is similar in sexes, reaching 25.1-26.5% of standard length in males and 24.6-27.1% of standard length in females; the head length is greater than maximum body depth; pre-orbital distance is less relative to the other freshwater Salariopsis species, reaching 29.1-31.6% of head length in males and 29.5-30.7% of head length in females (Ref. 89850). Simple (unbranched) thick supra-ocular tentacle shorter than eye-diameter; conspicuous cephalic pores on sensory canal, especially infra-orbital; supra-temporal canal with 3 cephalic pores; pre-operculo-mandibular canal with 7-9 cephalic pores; orbital canal with 8-9 cephalic pores (Ref. 89850). Teeth: 19-22 on upper jaw and 13-15 on lower jaw (Ref. 89850). Ventral fins are inserted anterior to origin of the dorsal fin; pre-ventral length is 86.3-92.7% pre-dorsal length in males and 87.1-95.5% in females; pectoral fin is 23.9-24.1% of standard length in males and 24.9-26.5% in females; anterior dorsal fin height is 9.1-11.7% of dorsal fin length in males and 10.5-10.7% in females; dorsal fin with 12-13 spines and 16-17 soft rays; anal fin with 2 spines and 16-17 soft rays; pectoral fin with 10-11 soft rays; pelvic fin with 2 spines and 2-4 soft rays (Ref. 89850, 128181). High caudal peduncle, minimum body depth 10.9-12.4% of standard length in males and 10.9-11.0% of standard length in females (Ref. 89850).

Colouration: Blue cephalic pores and blue blotches in gular region (Ref. 89850).