A single male of the Tequila Splitfin was sampled in 1955 by Miller and Greenbank, but identified erroneously as Zoogoneticus quitzeoensis, with which species it was collected and found sympatrically . Many years later, the mistake was detected, the fish identified as a new species and finally, 43 years after the first capture, described by Webb and Miller.

In 2001, a wild population of this species was rediscovered in a very small spring pool (3 x 4m in diameter). The population there was composed of only a handful of 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 was comparable in size to an aquatic stock) was higher than in any aquatic stock. In 2013 the loss of this population was reported (pers. comm. Domínguez), so there is not much hope that this species is still persisting in the wild.

Despite being a wholly unsuitable aquarium subject, C. idella is often traded as such, with an albino form having been developed specifically for the ornamental market.

Individuals which have outgrown their aquarium or pond should never be released into natural waters, either, since this species has proven capable of causing serious environmental damage under a wide range of climatic conditions.

H. compressus is the type species of the genus Hyphessobrycon but is not well-known in the ornamental trade.

Hyphessobrycon was raised by Durbin in Eigenmann (1908) as a subgenus of Hemigrammus, differing from the latter by the absence of scales on the caudal-fin.

Tends to be most common in brackish to hypersaline environments such as coastal salt marshes, lagoons and estuaries.

On San Salvador Island, Bahamas, it appears to be the parent of a species group occurring in sympatry and exploiting diverse but specific resources with some spectacular morphological adaptations.

The surrounding area is semi-arid and the Bolsón de Sandia was once a beautiful oasis with a number of springs, abundant vegetation and diverse wildlife but has dried up over the last twenty to thirty years due to indiscriminate water extraction for agriculture and other human uses.

Three endemic species of Cyprinodon, namely C. veronicae, C. longidorsalis and C. ceciliae, have been described from separate springs within the system…

Need not be too complicated so long as there are plenty of broken lines-of-sight.

Provide plenty of cover in the form of aquatic plants, wool mops, etc., and if using filtration air-powered, sponge-type units are best as these will not harm eggs or fry.

Lighting is unimportant but can be use…

El Pandeño de los Pando has a surface area of around 287 m² with depth ranging from 40-80 cm but there is an abandoned artificial channel which has an area of approximately 437 m².

Water temperature fluctuates between 38-48°C/100.4-118.4°F and the spring is considered one of the hottest environments inhabited by fish in the world.

The type locality originally consisted of a single spring-fed pond located in an endorheic basin known as ‘La Hediondilla’ at the foot of the ‘Cerro Potosí’ mountain and around 1880 m AMSL.

It had been modified to make it larger via an earth and rock dam, and below the pond were several distributaries running for a distance of 1-1.5 km.

Found in both Caribbean and Pacific-slope drainage basins in Central America, from southern Mexico through Belize, Guatemala, Honduras and Nicaragua, and into Costa Rica.

This species clearly shouldn’t ‚ be considered a home aquarium‚ subject at all given its eventual size and the fact it can live for‚ several decades.‚

Endemic to a handful of natural springs in the Río Verde valley, San Luis Potosí state, Central Mexico. The valley is believed to have once been filled by a large lake and the relict springs are part of the elevated Río (river) Verde basin which later drains into the much larger Río Pánuco system. Much of the aquatic fauna found in the valley is endemic to the area but in many cases threatened by introduced species.