Pregnant female guppies have enlarged and darkened gravid spots near their anal vents. Just before birth, the eyes of fry may be seen through the translucent skin in this area of the female's body. When birth occurs, individual offspring are dropped in sequence, typically over a period of one to six hours. The female guppy has drops of two to 200 fry at a time, typically ranging between 30 and 60.
Well-fed adults do not often eat their own young, although sometimes safe zones are required for the fry. Specially designed livebearer birthing tanks, which can be suspended inside the aquarium, are available from aquatic retailers. These also serve to shield the pregnant female from further attention from the males, which is important because the males sometimes attack the females while they are giving birth. It also provides a separate area for the newborn young as protection from being eaten by their mother. However, if a female is put in the breeder box too early, it may cause her to have a miscarriage. Well-planted tanks that offer barriers to adult guppies shelter the young quite well. Guppy grass, water sprite, water wisteria, duckweed, and java moss are all good choices. A continuous supply of live food, such as Daphnia or brine shrimp, keep adult fish full and may spare the fry when they are born. Young fry take roughly three or four months to reach maturity. Feeding fry live foods, such as baby brine shrimp, microworms, infusoria and vinegar eels, is recommended. Alternatives include finely ground flake food, egg yolk, and liquid fish food, though the particulates in these may be too large for the youngest fry to eat.
The guppy also known as millionfish and rainbow fish, is one of the world's most popular freshwater aquarium fish species. It is a member of the family Poeciliidae and, like almost all American members of the family, is live-bearing. They are highly adaptable and thrive in many different environmental and ecological conditions. Male guppies, which are smaller than females, have ornamental caudal and dorsal fins, while females are duller in color.
Guppies prefer a hard-water aquarium with a temperature between 78 and 82 °F. Guppies are generally peaceful, though nipping behavior is sometimes exhibited between male guppies or towards other top swimmers like members of the genus Xiphophorus (platies and swordtails), and occasionally other fish with prominent fins, such as angelfish. Guppies should not be kept as a single fish in an aquarium because both males and females show signs of shoaling, and are usually found in large groups in the wild. Its most famous characteristic is its propensity for breeding.
The black skirt tetra, petticoat tetra, high-fin black skirt tetra, black widow tetra and blackamoor, is a freshwater fish of the characin family (Characidae).
The black skirt tetra is often kept in aquariums. Growing up to 3.0 inches in length, the black tetra has a roughly tetragonal body shape and is greyish in colour, fading from near black at the tail to light at the nose. Two prominent, black, vertical bars appear just posterior to the gills. It is easily distinguished from all of its congeners by the presence of a dense field of dark chromatophores spread homogeneously over the posterior one half of the body unlike the lack of such pigmentation in all congeners.
The black skirt tetra is a schooling fish that feeds on small crustaceans, insects, and worms. The black skirt tetra is a common fish that is widely available for purchase. Hobbyists often provide live foods such as daphnia and mosquito larvae, and frozen foods like bloodworms.
The species reaches sexual maturity at about two years of age. Like most characins, this species spawns by intermittently releasing and fertilizing eggs among plants. It frequently eats its own eggs, so keepers remove the fish after spawning.
Oecilia 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 and coastal brackish and marine waters of Mexico. The molly can produce fertile hybrids with many Poecilia species, most importantly the sailfin molly. The male mollies generally tend to be mildly aggressive.
Mollies rank as one of the most popular feeder fish due to high growth rate, birth size, reproduction, and brood number. Contrary to popular belief, this species of fish is actually a freshwater species, spending little time in brackish water before swimming back to their freshwater biotope. Mollies appear to be a hardy and highly adaptable species (this has been diluted over years of interbreeding in tank-bred specimens).
Mollies are similar in appearance to their livebearer cousins, the platy, swordtail and guppies; the molly tends to be slightly larger and more energetic. Many aquarists note the stronger individuality and aggression in keeping mollies versus platies, who appear much more docile.
Standard size of male fish is 3.2 inches and female fish is 4.8 inches.
Selective breeding over centuries has produced several color variations and different body shapes.
Short-finned molly or common molly: They inhabit fresh water streams and coastal brackish and marine waters of Mexico. The wild-type fishes are dull, silvery incolor. The molly can produce fertile hybrids with many Poecilia species, most importantly the sailfin molly. The wild form is in fact quite rarely kept, as it has a rather plain silvery coloration suffused with brown and green hues.
Black molly: It is a melanistic breed 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.
White molly: A white colored molly.
Golden molly: Nicknamed the "24 karat".
Balloon molly: This fish has a deformed spine due to a genetic defect that gives it its appearance. Through selective breeding it is now widely available. Balloon mollies can still reproduce and live a normal life comparable to that of other mollies, but it has garnered controversy due to the belief that its defect gives it a shortened lifespan and a susceptibility to health problems.
Lyretail: A breed with an altered caudal fin structure.
Dalmatian molly: A silver colored breed with black speckles