Taxonomy & naming
Skiffia multipunctata was first described by the French ichthyologist Jacques Pellegrin in 1901, from fishes collected by Léon Diguet in the state of Jalisco, Mexico — material taken in the lakes and ditches of Agua Azul near Guadalajara, a type locality long since swallowed by the growing city. Pellegrin originally placed the species in the genus Xenendum, so the valid name today carries his authority in parentheses: Skiffia multipunctata (Pellegrin, 1901). The genus Skiffia itself was erected a year later, in 1902, by Seth Eugene Meek, who named it in honour of Frederick J. V. Skiff, the first director of the Field Columbian Museum in Chicago.
The species has accumulated a short tangle of synonyms reflecting a century of generic reshuffling among the splitfins: Xenendum multipunctatum (Pellegrin, 1901), Goodea multipunctata (Regan, 1907) and Ollentodon multipunctatus (Hubbs & Turner, 1937) all refer to this same fish. Eschmeyer's Catalog of Fishes treats Skiffia multipunctata as the valid combination, placing it in the family Goodeidae — the splitfins or goodeids — within the order Cyprinodontiformes, and in the live-bearing subfamily Goodeinae. The family is a Mexican radiation, largely endemic to the Mesa Central, and Skiffia is one of its better-known small genera, of interest to hobbyists for the readiness with which several of its members hybridise in captivity.
Morphology
Skiffia multipunctata is a small, deep-bodied splitfin: females reach the larger size, to roughly 2.5 in total length, while males stay smaller at around 2 in. The common and scientific names both point to the same feature — the body is marked with rows of small dark spots, one set roughly to each scale, which Pellegrin counted as five or six longitudinal rows of little brown dots. Over this base, individuals of both sexes can carry irregular, asymmetric black blotches that vary enormously from fish to fish, giving the hobby name "splotched splitfin."
Males are the showier sex and carry several diagnostic features. The defining one is the splitfin structure for which the family is named: the front rays of the anal fin are shortened and set off by a notch, forming the andropodium — the goodeid's intromittent organ, here built from roughly the first seven anal-fin rays and structurally distinct from the gonopodium of poeciliids. Mature males also develop a tall, notched and somewhat serrated dorsal fin, brighter colour with yellow-to-orange flanks, and in courtship a bluish sheen across the forehead. The black blotching is variable and individually distinctive; studies of mate choice in this species (Moyaho and colleagues, 2009) found that females actually reject the most heavily blotched males, so the melanism is not driven by simple female preference.
Habitat
The spotted skiffia is endemic to the highlands of west-central Mexico, in the states of Jalisco and Michoacán. Historically it occupied a broad swath of the upper Lerma–Santiago system: the lower Río Lerma drainage including the Río Duero, the Río Grande de Santiago and Laguna de Chapala (with satellite waters such as Laguna Cajititlán), and the Río Guascuaro in the headwaters of the Balsas basin. It is a fish of small lakes, quiet river channels, spring-fed ponds and irrigation ditches, typically in shallow water less than a metre deep over silt, mud, sand or rock.
Within those waters it favours vegetated, well-oxygenated margins — green algae, duckweed (Lemna), cattail (Typha), water hyacinth and the submerged roots of bald cypress (Taxodium) all feature in its habitat, the last providing both grazing surface and cover. Reported conditions are warm and tropical, with water temperatures around 77–82 °F in the wild and a latitude range of roughly 19–21 °N. The water it lives in ranges from clear to turbid, with no to moderate current. Much of this former habitat has been degraded or lost: the species is now extirpated from Lake Chapala, the Santiago basin and parts of the lower Lerma, and survives chiefly in the spring-fed lakes of the Río Duero drainage, the largest populations being in lakes La Luz and Orandino.
Feeding
Skiffia multipunctata is essentially a grazer, with a low trophic level (about 2.1 in FishBase's estimate) and the gut to match — a long intestine, roughly three times the body length, typical of fishes that process a great deal of plant and algal material. Both rows of jaw teeth are bifid, well suited to scraping. In the wild it grazes the aufwuchs and filamentous algae coating rocks, vegetation and submerged Taxodium roots, supplementing this with small aquatic invertebrates taken from the same substrate.
In the aquarium it is an unfussy feeder that should be offered a vegetable-leaning diet to suit its grazing biology: good-quality flake and small pellets with a high plant or algal content, blanched vegetables, and spirulina-based foods, rounded out with small live and frozen foods such as Daphnia, brine shrimp and bloodworm for condition and breeding. As with other goodeids, a steady supply of algae or vegetable matter keeps the fish in better health than an all-protein regime; frequent small feedings suit its near-constant grazing habit.
Mating
Like all goodeids, Skiffia multipunctata practises internal fertilisation, but by a mechanism quite separate from the poeciliid livebearers. Instead of the gonopodium of guppies and platies, the male carries an andropodium — a notched front portion of the anal fin formed from roughly the first seven shortened rays — which is used to transfer sperm to the female. This is one of the textbook examples of live-bearing evolving independently more than once within the toothcarps: the goodeid and poeciliid systems are not homologous.
Courtship in this species draws on the male's ornaments. Displaying males raise the tall, notched dorsal fin, flush their yellow-to-orange flanks and show a bluish sheen on the forehead, presenting themselves to females in the vegetated shallows. Mate choice has been studied directly: rather than favouring the most strikingly marked males, females of S. multipunctata were found to reject those with the heaviest black blotching (Moyaho et al., 2009), indicating that the conspicuous melanism is not maintained by female preference. The species is also known for hybridising readily with its congener Skiffia francesae in captivity — the so-called "Black Beauties" line documented by Langhammer in 1988 — which makes maintaining clean, separate stocks a real concern for conservation breeders.
Breeding
Skiffia multipunctata is viviparous, giving birth to live, fully-formed young rather than laying eggs. The live-bearing habit was evident from the very first specimens: Pellegrin's type series included a female carrying about ten well-developed embryos, one with its head already emerging from the genital papilla. Goodeid embryos are nourished internally through trophotaeniae — ribbon-like extensions that function rather like a placenta, drawing nutrients from the mother across gestation — so the young are born comparatively large and advanced. Broods are modest in size, on the order of a dozen young, fewer than a productive guppy but each fry better developed.
Breeding is seasonal in the wild, concentrated in spring: gravid females have been recorded at the La Luz spring in March, and newly released young are captured from roughly February through May. The species breeds readily in aquaria and is regarded as one of the easier goodeids to propagate, which is central to its survival in captive conservation programmes. As a colony breeder it generally does not hunt its own fry the way many poeciliids do, so young raised in a well-planted tank often survive alongside the adults; even so, dense vegetation improves fry recruitment. Captive larval ecology and development have been documented in the literature (Escalera-Vázquez et al., 2004; Kelley et al., 2005). To pace reproduction, keepers commonly impose a cooler winter rest below about 68 °F for two or three months, which halts fry production until spring.
In the aquarium
The spotted skiffia is a rewarding but slightly demanding aquarium fish, and one most likely to be encountered through goodeid-specialist and conservation channels rather than the general trade. It is best kept as a colony in a broad, low tank — height matters little, around 10 in is ample, but footprint does — of at least 15 US gal for a group. The species comes from cool, clean, well-oxygenated spring waters, and replicating that is the key to keeping it well: high dissolved oxygen (on the order of 8 mg/L), moderate current, and large weekly water changes of 60–80 percent.
Temperature is the husbandry point most often gotten wrong. Despite the warm figures sometimes quoted for its native waters, captive skiffias do best kept on the cool side, generally below about 75 °F, with a distinct cooler winter rest under 68 °F for a couple of months each year; sustained warmth shortens their lives and exhausts the females with continuous breeding. They are peaceful and well suited to a single-species or goodeid-community setup, but should never be housed with congeners they can hybridise with — keeping Skiffia multipunctata and S. francesae apart is a standing rule among serious keepers. Given clean, cool, oxygen-rich water and a vegetable-rich diet, it is a hardy and long-lived fish, which is precisely why it has become a mainstay of aquarium-based conservation.
Conservation
Skiffia multipunctata is assessed as Endangered on the IUCN Red List (assessed 14 March 2018, under criteria A2ac; B1ab+2ab), with a decreasing population trend. The drivers are the familiar ones for the goodeids of the Mesa Central: pollution, water extraction and falling water levels, habitat modification and the spread of introduced fishes. The species has already been lost from Lake Chapala, the Santiago basin and much of the lower Lerma; the type population at Agua Azul near Guadalajara is regarded as extinct, its waters now urbanised, and the Río Guascuaro subpopulation is treated as data deficient. In Mexico it is listed as Amenazada (threatened) under NOM-059-SEMARNAT-2010.
What survives in the wild is concentrated in a small number of spring-fed lakes of the Río Duero drainage — six or seven populations, the strongest in lakes La Luz and Orandino. Against that fragile wild footing, the species' relative security rests heavily on ex-situ conservation: it is a CARES Priority species and a focus of the Goodeid Working Group, and is bred in numbers by hobbyists and institutions specifically to hold a genetic reservoir outside Mexico. For an aquarist this reframes the usual ethic — keeping and breeding clean, well-documented, non-hybridised lines of Skiffia multipunctata is itself a conservation act, and the single most important husbandry rule is to keep those lines pure and never cross them with related splitfins.