Live-bearing fish, such as mollies, practice internal fertilization and gestation. The male has a modified anal fin called a gonopodium. During mating, the male inserts the gonopodium into the female's urogenital opening and deposits sperm. Before mating, the fish engage in a mating ritual involving fin displays.Know More
During mating, the sperm are transferred in a sperm packet. After about 15 minutes, the packet dissolves and releases the sperm. The sperm remain viable inside the female indefinitely and are nourished by sugars released from the ovaries. Each brood of fry can have multiple fathers. A female molly can become pregnant multiple times after mating just once. Every 2.5 months, a female molly gives birth to up to 60 fry. Unless separated from all males at an early age, most female mollies are constantly pregnant.
The eggs are released inside the mother, are fertilized and begin developing. The developing young rely entirely on the yolk stored inside the egg for nourishment. After a gestation period of about 4 weeks, the eggs hatch, and the fry are expelled from the body of the female. Mollies don't engage in any kind of parental care and eat as many of their own fry as they can catch.Learn more about Fish
When Molly fish are pregnant, they develop large, swollen abdomens with large dark spots near the pectoral fin. Mollies start to develop this appearance up to a week before giving birth.Full Answer >
Like all mollies, the black molly is a live-bearing fish. Mollies breed readily and are a good choice for novice fish owners.Full Answer >
How sharks reproduce varies and can include laying eggs in secluded nursery waters or giving birth to live pups after the lengthy internal gestation of eggs, but all sharks mate via internal fertilization during copulation. Nurseries are warm, shallow waters where young sharks are safe from large predators and can feed on the plentiful fish around them before swimming out into the open sea.Full Answer >
Betta fish changing color is known as marbling and is due to a genetic trait that determines the fish's color; it allows the fish to change coloration from one day to the next. The jumping gene can affect coloring and then reverse to reinstate the previous color.Full Answer >