GoldfishCarassius auratus auratus
Facts6.0 - 8.0
Crucian Carp, Edible Goldfish, Gibel Carp, Gold Crucian Carp, Golden Carp, Native Carp, New Zealand, Prussian Carp, Carp
Asia: central Asia and China, and Japan (Ref. 6390). Introduced throughout the world. Asian form of the goldfish (Ref. 1739). Several countries report adverse ecological impact after introduction.
Facts7.0 - 8.0
Guppies, Million Fish, Millions, Millions Fish, Rainbow Fish, Barbados Millions
South America: Venezuela, Barbados, Trinidad, northern Brazil and the Guyanas. Widely introduced and established elsewhere, mainly for mosquito control, but had rare to non-existing effects on mosquitoes, and negative to perhaps neutral effects on native fishes (Ref. 12217). Africa: Feral populations reported from the coastal reaches of Natal rivers from Durban southwards, as well as in the Kuruman Eye and Lake Otjikoto in Namibia (Ref. 7248). Several countries report adverse ecological impact after introduction.
DescriptionThe guppy (Poecilia reticulata), also known as the millionfish, is one of the most popular freshwater aquarium fish species in the world. It is a small adaegus member of the Poecilidae family (females 4-6 centimetres long, males 2½–3½ centimetres long) and like all other members of the family, is live-bearing.
Green Swordtail Xiphophorus hellerii
Facts7.0 - 8.0
Red Swordtail, Swordtail, Swordtails
North and Central America: Rio Nantla, Veracruz in Mexico to northwestern Honduras. Africa: Feral populations reported from Natal and eastern Transvaal as well as in Lake Otjikoto, Namibia (Ref. 7248). Several countries report adverse ecological impact after introduction.
DescriptionThe Green swordtail (Xiphophorus hellerii) is a species of freshwater fish in family Poecilidae of order Cyprinodontiformes. It is also called Red swordtail. A live-bearer, it is closely related to the southern platyfish or "platy" (X. maculatus) and can interbreed with it. It is native to an area of North and Central America stretching from Veracruz, Mexico, to northwestern Honduras.
The male green swordtail grows to a maximum overall length of 14cm (5.5in) and the female to 16 cm (6.3 in).The name "swordtail" is derived from the elongated lower lobe of the male's caudal fin (tailfin). Sexual dimorphism is moderate, with the female being larger than the male but lacking the "sword". The wild form is olive green in color, with a red or brown lateral stripe and speckles on the dorsal and, sometimes, caudal fins. The male's "sword" is yellow, edged in black below. Captive breeding has produced many color varieties, including black, red, and many patterns thereof, for the aquarium hobby.
The green swordtail prefers swift-flowing, heavily-vegetated rivers and streams, but is also found in warm springs and canals. Omnivorous, its diet includes both plants and small crustaceans, insects, and annelid worms.
Xiphophorus hellerii has become a nuisance pest as an introduced species in a number of countries. It has caused ecological damage because of its ability to rapidly reproduce in high numbers. Feral populations have established themselves in southern Africa, including Natal, Madagascar and eastern Transvaal in South Africa and Lake Otjikoto in Namibia. Significant populations have also established themselves along the east coast of Australia.
One of the most popular tropical aquarium fish, the green swordtail has been bred into various hybrid forms for the aquarium hobby due to its hardiness and suitability for community tanks.
The green swordtail, as the most common of the swordtail species (and in recognition of the fact that many captive-bred color varieties are not green), is typically known simply as the swordtail in the aquarium hobby. It is often designated X. helleri (with one i), but authorities consider this an orthographic error and the spelling with two is is the valid specific epithet. Due to interbreeding with the southern platyfish or "platy" most "swordtail" in the aquarium are hybrids to some degree.
The males' elongated caudal fins have been found to significantly affect their chances at mating. The presence of a well-endowed male spurs the maturity of females while it inhibits the maturity of juvenile males in the vicinity of the well-endowed male.
DescriptionPoecilia sphenops is a species of fish, of the genus Poecilia, known under the common name Molly; to distinguish it from its congeners, it is sometimes called Short-finned Molly or Common Molly. They inhabit fresh water streams, coastal brackish and marine waters of Mexico. The wild-type fish are a dull silvery color, often sprinkled black all over.
Contrary to popular belief that these fish are a brackish water species that prefers some salt in their tank, this species of fish is actually a freshwater species spending little time in brackish water before swimming back to their freshwater bio-type. However, fish of the same species have been found in coastal sea waters, brackish swamps and freshwater streams happy and breeding. It appears Mollies are a hardy and highly adaptable species (this has been diluted over years of inter-breeding in tank-bred specimens).
This species is one of the ancestors of the black mollies, a number of melanistic breeds which are black all over. It is one of the most well-known aquarium fishes and nearly as easy to keep and prolific as guppies (for optimal health and breeding success, they demand fresh vegetable food like algae). There are several other popular breeds, like the golden molly nicknamed "24 karat", or the balloon molly, which however has a deformed spine and a decreased lifespan due to the associated health problems. Also, breeds with altered caudal fin structures like lyretails exist. The wild form is in fact quite rarely kept, as it has a rather plain silvery coloration suffused with brown and green hues. If given good care with ample sunlight, high water temperatures and fresh vegetables, they will, however, prove charming fish who make up for their somewhat plain coloration with their lively behavior.
The common molly can produce fertile hybrids with many Poecilia species, most importantly the sailfin molly. In the case of black hybrids, they are called midnight molly. These are very popular due to their impressive dorsal fins, but require a bit more attention and have a somewhat decreased lifespan - though certainly not as much as the deformed breeds.
The male black mollies generally tend to be mildly aggressive. Although they are compatible tankmates with fish like the tiger barbs, they will chase them.
Mollies rank as one of the most popular feeder fish due to high growth rate, birth size, and brood number.
Apteronotid Eel Apteronotus albifrons
DescriptionThe black ghost knifefish, Apteronotus albifrons, is a tropical fish belonging to the ghost knifefish family (Apteronotidae). They originate in South America in the Amazon Basin in Peru and from Venezuela through Paraguay in the Paraná Rivers. They are becoming popular in aquaria. The fish is all black except for two white rings on its tail, and a white blaze on its nose, which can occasionally extend into a stripe down its back. It moves mainly by undulating a long fin on its underside. It will grow to a maximum length of 25 inches (60 centimeters). It does not have scales.
They are nocturnal, but they are weakly electric fish and use an electric organ and receptors distributed over the length of their body in order to locate insect larvae. Along with Peters' elephantnose fish they are the most studied of the active electrosensing fish.
The black ghost knifefish natively lives in fast moving, sandy bottom creeks in a tropical climate. They prefer water with a 6.0 - 8.0 pH, a water hardness of 5.0 - 19.0 dGH, and a temperature range of 73-82 F (23-28 C).South American natives believe that the ghosts of the departed take up residence in these fish , hence the name.