While most fish lay eggs, live birth (viviparity) is surprisingly common in certain groups, with estimates suggesting around 2% of all fish species give live birth, but this jumps significantly in some families, like 70% of sharks and up to 27% of Cyprinodontiformes (killifish, guppies). Overall, it's a rare trait in the vast majority of fish, but a successful evolutionary strategy in others.
Not all fish lay eggs—some give birth to live young! Swordtails, mollies, and platies are popular freshwater fish that do just that. Keeping them is easy—just add males and females, and soon you'll have baby fish. In a few weeks, you'll see tiny swimmers exploring the tank.
Fish. Live birth is also rare in fish, accounting for about two percent of known species, including guppies and sharks.
There are well over 300 species of livebearers across about 70 genera of freshwater fish. Indeed, there are actually many more livebearers if you account for all the geographic populations and cultivated varieties.
Is Fish Giving Birth in an Aquarium Considered Good or Bad? Generally, fish giving birth in a home aquarium is interpreted as a positive omen. It symbolises prosperity, protection and removal of adversities.
In fish with long gestation periods, like sharks, it may be difficult to notice the pregnancy for many months. Many species of fish can get pregnant and give birth every 4 to 8 weeks. Fish like sharks take much longer to give birth, and so they may not produce offspring more often than once or twice every few years.
Separating the fry from the adults not only prevents them from being eaten, but it also allows them to grow bigger and faster because there is less competition for food. Additionally, it is best to keep the newborns in a smaller container so that they don't have to expend as much energy swimming to reach their meals.
With an average life expectancy between 5 and 7 years, livebearers are relatively long-lived. This allows most hobbyists to witness the birth of several generations of fry. In fact, one of the most fascinating aspects of keeping livebearers is the rearing of young fry.
The #1 rarest fish is often considered the Devil's Hole Pupfish (Cyprinodon diabolis) due to its incredibly small habitat in a single Nevada cavern, though some sources cite the Red Handfish as rarer, with only around 100 individuals left in Tasmania; both face critical endangerment, but the Pupfish lives in the smallest known home for any vertebrate.
Incubation. After about 30 days, the fish embryos develop visible eyes, or "eye up". We then safely sort the live versus dead and count these now "eyed up" eggs. About 10 days later, or 40 days after initial fertilization, the "eyed up" eggs hatch into baby fish, known as "alevin".
And most fish don't care for their young, but out of the species that do, between one-third and one-half rely on fathers parenting alone. Perhaps the most well-known example is the seahorse, where the male becomes pregnant, carrying his mate's fertilized eggs in a pouch on his belly until they hatch.
Egg laying almost certainly came before live birth; the armored fish that inhabited the oceans half a billion years ago and were ancestral to all land vertebrates seem to have laid eggs.
An international team of scientists has sequenced the genome of the Amazon molly, a fish that reproduces asexually. The researchers expected that the asexual organism would be at a genetic disadvantage, but the Amazon molly is thriving.
How to Prevent Livebearer Disease
Nearly all fish reproduce by sexual reproduction. A more unusual form of asexual reproduction found in a few fish species is parthenogenesis, which is where the female egg develops into a new individual without fusing with a sperm cell.
Guppies are livebearers, meaning they give birth to live young rather than laying eggs. This is because the eggs develop inside the female's body and hatch before being expelled, a process known as ovoviviparity from Swell UK. The technical term for this is viviparous reproduction.
Fish worth a million dollars are typically rare, high-quality bluefin tuna sold at Japan's New Year auctions for prestige and good fortune, or exceptionally rare Japanese koi bred for unique colors and patterns, with recent sales reaching over $3 million for tuna and $1.8 million for koi. These prices reflect cultural value, culinary demand, and the fish's status as a collector's item rather than just food.
Article Content. The scales of the massive Amazonian freshwater fish, Arapaima gigas, are so tough that they do not tear or crack when a piranha—which has one of the animal kingdom's sharpest bites—attacks.
The Red Handfish (Thymichthys politus) is one of the rarest fish on Earth. Unlike most fish, it "walks" across the seafloor using modified pectoral fins resembling tiny hands. Found only in shallow waters off Tasmania, Australia, it crawls slowly along sandy seabeds and seaweed patches.
According to tank scapping, most fish recognise their owners or more precisely their feeders. Particularly those that swim higher in the water column quickly learn when feeding time is and who feeds them. But some species can truly recognise human faces.
Whether it be their genetics or due to the cold conditions they live in and more, there are a lot of species that live for decades, if not longer. One species known for its long lifespan is the rougheye rockfish, a deep-sea fish which can live for over 200 years.
Tap water is safe for your tank so long as you treat it with a water conditioner to remove harmful toxins and chlorine.
Depends on the fish. Big fish that like to carve out large territories crammed in small tanks or highly social fish left in a tank alone is going to stress them out. Pairing incompatible or agressive fish is also stressful as they may harass (or worse) eachother.