Abstract;

A new species of cloud fish of the genus Hypsolebias is described from a temporary pool in the rio Trairi basin, Rio Grande do Norte State, Brazil. It is the first record of the genus Hypsolebias for the basin. The new speciesbelongs to the H. flammeus species-group, which is composed of the species H. alternatus, H. brunoi, H. delucai, H. fasciatus, H. longignatus, H. marginatus, H. multiradiatus, and H. flammeus. The new species differs from all other species of the group, except H. flammeus, H. multiradiatus,and H. brunoi, by male color pattern and the presence of a metallic blue sheen surrounding the black spots of females. It differs from H. flammeus, H. multiradiatus and H. brunoi by dorsal and anal fin shape (both rounded vs. pointed) and by the orientation of the reddish-brown bars on the body and anal fin of males (diagonal vs. vertical). The new species differs from its congeners of Northeast Brazil mainly by the higher number of dorsal fin rays in males and the higher number of scales in the longitudinal series.

First discovered by; Alberto Antônio da Silva Gomes

Hypsolebias is currently the cloud fish genus with the greatest number of described species.

It has a wide geographical distribution among watersheds that make up the four continental freshwater ecoregions of the Caatinga, with 32 described species: one species in the state of Parnaíba (PAR), three in Northeastern Caatinga and Coastal Drainages, 27 in São Francisco and one in Northeastern Mata Atlantica. Another seven representatives are found in the rio Tocantins basin and ecoregion in the Brazilian Cerrado.

The genus Hypsolebias is one of the most endangered continental fish groups in the Caatinga, with around 20 endangered species, according to recent lists and official ordinances .

These 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 3 to 5 months.

Remark:

Let us hope this nice new species finds its way to the breeders worldwide.

(working on it;)

Max. size 00 mm in males - female smaller.
Dorsal (average, male only ) 00.0,
Anal (average, male only ) 00.0,
D/A (average, male only ) 0.0,
LL scale count (average) 00.0
Pre- dorsal length to SL – 00.0 %
Depth to SL – 00.0 %
Vertebrae count (average) 00.0

Ramos TPA, Nielsen DTB, Abrantes YG, Lira FO, Lustosa-Costa SY. A new species of cloud fish of the genus Hypsolebias from Northeast Brazil (Cyprinodontiformes: Rivulidae). Neotrop Ichthyol. 2023; 21(3):e230068. https://doi.org/10.1590/1982-0224-2023-0068