The species was discovered in the headwaters of the Rio Zapatilla drainage in a river with the name Rio Camellaque, at about 24 km along the Ilave - Mazo Cruz-road near Tiutiri, Chucuito Province, Peru. It is the only known locality so far.

The name reflects the feature that this fish separates from its congerers by having ctenoid scales all over the body.

It belongs to the Orestias agassizii species group.

Morphology and color pattern strongly suggests the species is synonymous with Orestias agassizii agassizii.

Coloration of Orestias ctenolepis changes with age. Juvenile males and females look almost the same. They show a dark longitudinal band that widens while aging and adult fishes become dark chocolate brown in males. Unpaired fins have pale brown colors and dorsal is darker than the others. Females, when adult, are more silvery gray with a dense pattern of gray spots on head and sides. Unpaired fins show no color and have some spots at the base.

Members of this genus have been generally maintained and bred only under controlled laboratory conditions rather than as aquarium fishes. Therefore, information about maintainance and breeding is present here as part of the general information about the genus rather than under each individual species. This information is based mainly on that obtained in the laboratory of the zoological Institute and zoological Museum, Hamburg (Villwock, 1995b)

Keeping and breeding Orestias species in captivity requires that the water is relative cool with temperatures between 10 and 15 C. Optimal water temperatures would be about 13 C.

Today it is believed that the species from the genus Orestias reach sexual maturity when they still display juvenile coloration and morphology. At that stage it is very difficult to recognise the sexes.

Eggs are deposited one by one or in a small cluster in fine substrate like live plants with fine leaves. Development of the eggs takes about 4 weeks due to the low temperatures the eggs should be stored. Youngs grow slow and can be fed by artemia nauplii and small worms and crustaceans

Remarks :

Because this special treatment the genus Orestias is seldom found in the tanks of hobbyists.

Source:

R. Wildekamp, "A world of Killies" , Volume 4.

Max. size 7.0 cm.
Dorsal 12-15,
Anal 14-15,
LL scale count 31-34

Morales, P., Gajardo, F., Valdivieso, C. et al. Genomes of the Orestias pupfish from the Andean Altiplano shed light on their evolutionary history and phylogenetic relationships within Cyprinodontiformes. BMC Genomics 25, 614 (2024).

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