This species was originally described as Simpsonichthys igneus.

W. Costa (2006) assigned many members of the genus Simpsonichthys to the subgenus Hypsolebias (Costa 2006). Hypsolebias was subsequently elevated to a genus (Costa 2011). According to some scientists, the separation of Hypsolebias from the genus Simpsonichthys is insufficiently substantiated and, therefore, debatable.

Discoverer(s): Wilson J.E.M. Costa et al., May 10. 2010.

Type locality: near road BA-381, about 2.5 km Filadélfia, das Jacas Creek, upper Itapicuru river basin, municipio de Filadélfia, Bahia state, altitude 415 m, (eastern) Brasil.

Etymology: with naked (from Latin: nudi) orbit (from Latin: orbitatus), in reference to the rudimentary or absent squamation on the supraorbital region.

Superspecieso-components: 

H. coamazonicus, H. faouri, flagellatus, flavicaudatus, ghisolfii, gilbertobrasili, guanambi, heloplites, igneus, janaubensis, macaubensis, martinsi, mediopapillatus, nitens, nudiorbitatus, pterophyllus, radiseriatus, sertanejo.

Diagnosis: a single, small scale on the posterior part of the supra-orbital region, sometimes absent (vs. usually 2 scales, sometimes 1 or 3 scales, occupying the whole supra-orbital region) (Costa, 2011b).

Hypsolebias nudiorbitatus is recently described. The species is part of the so called "H. flavicaudatus species group"

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This species can be productive, and the fry is small. Immediately after hatching, the fry should be fed with freshly hatched Artemia nauplii (brine shrimp) or better Paramecium. As most annual species do, they spawn by diving entirely into the substrate. It is best to provide a container with a lid on top in which a hole is made to allow the fish access. That container will need to have enough peat in it for the fish to dive completely into it. For most Hypsolebias species, egg development is complete after 8-10 weeks. However, it is wise also to check a few weeks earlier to see if any eggs have fully developed. Do not let the peat dry too far because the Hypsolebias like it moist. The development will be slower at storage temperatures between 21 and 24 Celsius and speed up at 25-29 Celsius. Before watering the eggs, put some eggs in the water of about 18-20 degrees Celsius to see if the eggs hatch correctly. That usually happens within 2-6 hours. Then, if eggs hatched well and fry, swim correctly, bring all remaining peat in the water. You may need to re-pack the peat after pouring over the first group of fry to a larger tank.

With regular water changes and sufficient food, the young will grow quickly, and after about 5-6 weeks, they can already produce their first eggs. Since this genus has an annual life cycle, the expected life span in captivity is not much more than 10 to 12 months. Their life expectancy is limited to when their pool still has water in the wild. This period can vary from 6 to 8 months.

Remark:

It is unfortunate that many species that were described never reached the fanciers. This is because newly discovered species are placed in alcohol shortly after their discovery and description. Since Brazilian regulations prohibit the keeping and distribution of these species within their own country and beyond, it is impossible to take photos of these species, and only photos from the original description can be taken.

Max. size 6.0 cm.
Dorsal 21.5,
Anal 22.0,
D/A 5.3,
LL scale count (average)29.0
Pre- dorsal length to % SL – 48.2 %
Depth to % SL – 29.5 %