Ascotan Mountain killifish
Orestias ascotanensis
FAMILY
Cyprinodontidae
TAXONOMY
Orestias ascotanensis Parenti, 1984, Salar de Ascotan, Chile.
OTHER COMMON NAMES
English: Lake Ascotan Mountain killifish
PHYSICAL CHARACTERISTICS
Grows to 2.4 in (6 cm) in length. A member of the Orestias agassizii species complex. Basically olive-green in color, with anal and dorsal fins set back and over each other. The lower jaw turns up. Males and females are robust, with a relatively large head compared with the heads of other species in the species complex. Sexually dimorphic and dichromatic. Males are smaller than females and more slender. Breeding males have a bright yellow overlay on the sides and the anal and dorsal fins. Females are larger and more rounded than males. The fins and body are mottled, tending toward more uniform coloration when they are very mature.
DISTRIBUTION
Known only from Salar de Ascotan, a small saline lake in northwestern Chile, the southernmost population of Orestias.
HABITAT
The species is found in the slightly brackish water of Lake Ascotan and its associated ponds, where Ruppia filifolia is the most common vegetation.
BEHAVIOR
In 1995, for the purpose of studying captive breeding, Jara, Soto, and Palma set up four males and four females in a planted 3 gallon (12 L) aquarium with no reported aggression among the males. The males did not persistently court the females, as happens with many other killifishes; some time was spent apart, feeding and moving about the aquarium.
FEEDING ECOLOGY AND DIET
In aquaria the species readily feeds on insect larva, crustaceans, and commercial flake food, indicating that in the wild it is a benthopelagic feeder on aquatic invertebrates.
REPRODUCTIVE BIOLOGY
This species is a typical plant spawner. At the lake, eggs were found attached to the vegetation. In aquaria the male courts the female by approaching from beneath and nudging her pelvic area. The two then move to the vegetation. With the pair positioned side by side with their vents close together, the male assumes a typical S-shape posture. The female releases two or three adhesive eggs, which are fertilized by the male. The filamentous eggs adhere to the vegetation. The incubation time is about 17 days at 63–68°F (17–20°C).
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
None known.
