Leptolebias opalescens was described in 1942 by Myers originally as Cynolebias opalescens, discoverd at Serra do Petropolis in the State of Rio de Janeiro, were they lived in waterholes at the foot of the mountains, now known as Serra dos Orgãos.

Coordinates are approx. 43º 15' W: 22º 35' S.

The species was placed in the than new erected genus Leptolebias by Costa in 1990. Other valid members in this genus are L. areoguttatus, L. itanhaensis, L. leitaoi, L. marmoratus and L. splendens. In 2008 Costa took 3 species out of th Leptolebias genus and placed them in a new genus named Notholebias. These three species are N. cruzi, N. minimus and N. fractifasciatus.

Max. size 4.0 cm.
Dorsal 13.0,
Anal 18.0,
D/A 4.0,
LL scale count (average)26.0

Myers, G.S. 1942. Studies on South American Freshwater Fishes I. Stanford Ichthyological Bull., 2 (4): 107.

Costa, W.J.E.M. 2016. Comparative Morphology and Classification of South American cynopoeciline killifishes (Cyprinodontiformes: Aplocheilidae), with Notes on Family-group Names used for aplocheiloids. Vertebrate Zoology, 66 (2): 129.