The discoverer from Kryptolebias brasiliensis was the wel known and famous explorer Baron Alexander von Humboldt. Humboldt found the species most likely near Rio de Janeiro but did not mention this and mentionned only "Brasil" as locality. The discovery took place between 1799 and 1804.

A. Valnciennes was the describer in 1821 a major work named "Voyage de Humbold et Bonplant by F.H.A Humbold & Valenciennes. He described the species as Fundulus brasiliensis wich became assigned to the genus Rivulus after the erection of that genus by Poey in 1860. Nowadays the genus has changed again by the work of Costa (2004) that placed them as Type species in the new erected genus Kryptolebias.

Myers described in 1924 Rivulus dorni that is seen as synonyme to K. brasiliensis.

The reproduction of Kryptolebias brasiliensis does not differ from all Rivulus with the exception that they breed better if water is not to soft. They like however also low pH and dark coloured water as well. In my experience they like to have a little salt added to the water and react by that in producing more fertile eggs and better resistence against sicknesses.

Eggs develop after 18 days and young fry eat baby artemia nauplii the day they get out their eggs.

They grow slow and after 5 - 6 months become adults. Eggs are large for the species size up to approx. 2 mm.

Max. size 6.0 cm.
Dorsal 9.0,
Anal 12.7,
D/A 7.1,
LL scale count (average) 31.5
Pre- dorsal length to SL – 73.6 %
Depth to SL – 21.3 %