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any of more than a thousand species of small fish of the several families of the order Cyprinodontiformes (toothed minnows or toothed carps), a group that includes also the topminnows and many popular aquarium fishes (e.g., the guppy or rainbow fish, Poecilia reticulata) among its brightly colored tropical species. Most North American toothed minnows are oviparous, i.e., bearing young hatched from eggs, and some are quite colorful; however, the tropical viviparous species (i.e., bearing live young) are preferred for aquariums, since they are easier to raise. Killifishes average from 2 to 4 in. (5–10 cm) in length and have compressed bodies, small mouths with projecting lower jaws, unforked tails, and large scales. They live in ponds, streams, ditches, and salt marshes throughout the United States and feed on insect larvae, crustaceans, and small water plants. The banded killifish is found in the Mississippi basin; the common killifish (5 in./12.5 cm) is an eastern species. Guppies can survive temperatures of up to 100°F; (38°C;) as can certain topminnows of the W United States. The greenish-gray female guppy (1 1-2 in./3.75 cm) produces from 12 to 25 live offspring every few weeks; in captivity they must be separated from the cannibalistic adults. The rainbow colors of the male guppy (1 in./2.5 cm) are marked with black spots and bars. Like the guppy, the 2-in. (5-cm) Gambusia, a topminnow of the S Atlantic and the Gulf, bears live young and is important in controlling mosquitoes, on whose larvae both the guppy and the minnow feed. Killifishes are classified in the phylum ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
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, subphylum Vertebrata, class Actinopterygii, order Cyprinodontiformes.
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References in periodicals archive ?
Microsatellite documentation of male-mediated outcrossing between inbred laboratory strains of the self-fertilizing mangrove killifish (Kryptolebias marmoratus).
During the Santa Clara event the other native species were rare, namely partially-armored threespine stickleback, California killifish, striped mullet, and staghorn sculpin.
The African annual killifish, officially named Nothobranchius furzeri, also faced the same problem but turns out they've condensed their lifecycle according to the available time.
Only six red shiners and two plains killifish were captured in spring 2006, and neither species was caught during the next fall event.
Wildlife ecologist at the Department of Environment and Natural Resources in Bermuda Dr Mark Outerbridge said: "Chester Zoo has proven to be a valued ally in the ex-situ breeding and husbandry of four island endemics (the killifish, a skink and two species of land snails).
The ability of many endocrine-disrupting compounds to partition in water has led to the use of fish models, including zebrafish, medaka, killifish, and mosquitofish (Gambusia affinis), in studies on their effects on health.
Differential sensitivity to pro-oxidant exposure in two populations of killifish (Fundulus heteroclitus).
"By collaborating with other zoos and aquariums across the world as part of ZSL's Fish Net project, it's great that we're able to work together for wildlife offering hope to species such as the characodon and killifish."
It is a diverse group of annual fish, most popularly known as "killifish", with about 350 valid species which occur from South of Florida, in the United States, to the Northeast of Argentina (Costa, 2011).