Zoogoneticus tequila

First Describer: 
Webb & Miller, 1998
Original Description: 

WEBB, S.A. & MILLER, R.R. (1998): Zoogoneticus tequila, a new goodeid fish (Cyprinodontiformes) from the Ameca drainage of Mexico, and a rediagnosis of the genus. Occ. Pap. Mus. Zool. Univ. MI 725: pp 1 - 23


This species is named for the mexican volcano Tequila, which looms north of the type locality.


Collection-number: UMMZ 233655. The Holotype is a mature male of 26.7mm SL, collected by R. R. Miller and J. T. Greenbank, 25.03.1955.

English Name: 
Tequila Splitfin
Mexican Name: 
Picote tequila

Zoogoneticus sp.    Lambert, 1990


2n = 46    2M/ 2m/ 42stt    (following Webb & Miller, 1998)

The maximum known SL is 48mm (Mi8ller et al, 2005).
Terra typica: 

The Holotype comes from the Río Teuchitlán, at the east end of Teuchitlán in Jalisco.

Status after IUCN: 

Critically endangered

Status after J.Lyons (2011): 

Endangered; Comment: One tiny population


This species is restricted to the Río Teuchitlán of the Río Ameca drainage from the Pacific Slope in Jalisco.


The habitat is a shallow and open lake-like exapandation of the Río Teuchitlán, 8m in diameter and 1.3m deep. The species prefers depths of less than 1m. The substrates are mainly mud and silt, a few rocks  and sand is present. The currents are none to moderate and the water is warm (about 26°C in March) and continuously turbid by cattle, pigs and horses. Few plants are living there: Eichhornia, a broad-leaved Potamogeton and hyacinth-like plant.


Adult males are dark olivaceous on the sides, back, nape and top of the head. Mottling is present on the side of the body, which often has a greenish hue. Many of the lateral scales are reflective, producing iridescense. The colour fades to pale yellow below the lateral scale series on the belly and below the eye. There is a pair of spots, which usually coalesce, at the base of the caudal fin. The mottling and the basicaudal spots may not be visible during breeding condition, when the body is darkest, nearly black. The unpaired fins are dark, fading towards the margins, with the pigmentation concentrated  along the lengths of the rays. The greenish cast of the body can occasionally be seen in the dorsal and anal fins. The borders of the dorsal and anal fins have a thin cream-coloured band. The caudal fin has a broad subterminal red to orange band, and the region proximal to this band is heavily melanized. The pelvic fins occasionally show some terminal cream colouring, but the pectoral fins are unpigmented. Females are olivaceous. The sides, back, nape and top of the head are dark and display mottling, while the belly below the lateral series and the area below the eye are pale yellow. Two to four large spots are found on the ventral half of the caudal peduncle. These spots occasionally fade in older individuals. A pair of basicaudal spots, which typicaly coalesce, are visible in most specimens. The unpaired fins may be dusky, but are not dark, and do not possess the cream-coloured margins that males display. Occasionally large females show a thin subterminal band of red-orange in the caudal fin, but it is less intense than in males. The unpaired fins are clear.


There is not much known about this species in the wild, due to its fast disappearance. Webb and Miller determined, that both sexes become mature within ten weeks when kept by 26-28°C. This could take more time in the wild with lower temperatures. Broods numbered as many as 20 - 29 offspring, fewer than 10 in the first year.


The teeth are conical and the gut is short. Combined with a small mouth, this species is a predator, picking small invertebrates like crustaceans and insect larvae. 


The Tequila Splitfin has been caught first in 1955, but has been identified erroneously as Zoogoneticus quitzeoensis (UMMZ 172224). Many years later, the mistake had been detected and the fish had been identified as new species. Finally, 43 years after the first capture, it has been described.


In 1955, when the fish has been taken first, all of the fish at the type locality have been abundant, including Skiffia francesae (though the water has been turbid by a lot of domestic animals). In 1990, it was still present (also Allotoca maculata) whereas Skiffia francesae had disapperared. Several exotic species have been introduced in the habitat. After 1992, collections have been unsuccessful. Intensive sampling in 1996 failed to reveal any Goodeids in the type locality. So it took human not even 40 years to extirpate consequently all species of Goodeids in only one habitat.


Brian Kabbes detected a young but mature male at the Balneario Teuchitlán in 1999, which gives hope, that the species is still existing there.


In 2001, a wild population of this species has been detected within a vey small spring (the locality is being kept as a secret), being composed of only a handful adult fish and a few tens of juveniles (De la Vega-Salazar et al., 2003). In 2007, N. W. Bailey et al showed, that the allelic richness of this population (though it is comparable in size to an aquatic stock) is higher than in any aquatic stock.


This species has been used by A. Arbuatti and P. Lucidi to survey, wether the environmental structure of a tank leads to a change or loss of behavorial richness. Due to the fact, that differences have not been found between enriched tank set ups and natural structures, the study encourages the breeding in captive conditions to conserve this species for reintroduction in the natural environment.


A short time ago, the Goodeid Working Group started a reintroduction project for this species, becoming more specified and well-defined now. The name for this project is "Viva tequila" and it shall encompass strategies to get the local residents on board, the building of semicaptive ponds for acclimatation of captive bred fish, the reintroduction of the fish and a monitoring and scientific guidance over 2 years.


 Images 1 and 2: males

Copyrights by Frank Kroenke

Image 3, 4 and 5: spawning pair

Copyrights by Frank Kroenke

Image 6: face of a male

Copyright by Frank Kroenke

Image 7: competiting males

Image 8: pond-raised male

Copyright by Martin Ravn Tversted/ Lars Vig Jensen

Image 9: male

Image 10: female

Images 11 and 12: pair

Image 13: male

Image 14: male

Image 15: pair