Everything You Need to Know About Live-bearers

Livebearers come in various patterns and colorations and can add a lot of excitement and beauty to community tanks. Whether you’re a beginner or an experienced aquarist, livebearers can easily thrive and multiply without much effort despite their fragile appearance.

What are Livebearers?

To put things simply, livebearers are fish that give birth to free-swimming young instead of laying eggs on rocks. Sharks are one of the first marine creatures


that started to give birth to live, free-swimming babies instead of eggs that need to be fertilized, simply because fertilization inside the body ensures a greater chance of survival as compared to fertilization outside the body. This is why livebearers are often easier to breed than egg-laying fish; fry can often hide and move around the tank, whereas eggs are stationary and could easily be eaten by tank mates.

There are plenty of livebearers in the hobby, but oftentimes livebearers refer to a group of fish in the family Poeciliidae. Freshwater fish that belongs to this group would be the rather ubiquitous guppies, platies, swordtails, and mollies.

General Livebearer Care

Livebearers are naturally hardy and can be happy in a wide range of aquarium conditions. It’s advised, however, to keep them in a planted tank that allows them to explore and scour the tank for natural food. Plants also act as natural filters, pulling out nitrates, nitrites, and ammonia.

Silver Lyretail Molly
Silver Lyretail Molly

Take note that while livebearers are generally peaceful, it’s important to have the appropriate ratio of males to females. Generally, it’s best to keep a 1:2 ratio of males to females, as livebearers constantly spawn and will therefore tire out the females to death if there are too many males.

In terms of tank size, guppies can do quite well in a 10-gallon tank or bigger, if you were to allow breeding to happen. If you don’t plan on breeding them, however, you can put them in smaller tanks and opt to purchase only male guppies (they’re usually the ones with larger flowing fins). As for swordtails and platies, however, take note that the females can grow up to 4 inches in size, almost as big as a juvenile goldfish! This would mean that you’ll need at least a 20-gallon tank to give them enough space to grow and thrive. As for mollies, they’re often the most adaptive species, as it’s able to adapt even in a full reef environment! This means that even in tanks smaller than 10 gallons, they can still thrive. In any case, just make sure that your filtration is adequate and your ammonia and nitrite levels stay at zero.

Feeding Live Bearing Fish

Livebearers are omnivores, which basically translates to eating everything that can fit in its mouth. This is both a good and a bad thing. It’s good, in a sense that it’ll thrive eating whatever it finds inside the tank together with regular pellet and flake food and the occasional live, frozen, or freeze-dried treats like bloodworms or brine shrimp. It’s bad, in a sense that if you have smaller fish or invertebrates in the tank, such as baby fish or red cherry shrimp, then their chances of surviving are dismal, especially if your tank isn’t densely planted.

Live Bearers Life Span

Livebearers typically live for about 5-7 years, and throughout the course of their lives you’re bound to get several generations of fish. In fact, a lot of hobbyists start with a trio of livebearers (2 females, 1 male) and end up with hundreds or even thousands of babies in just a few months! That being said, let’s talk about how one breeds livebearers.

Breeding Live Bearers

No matter how experienced one is in raising fish, the birth of tiny, free-swimming fish in an aquarium is always an exciting experience; imagine getting hundreds or thousands of babies that’ll eventually develop their own distinct patterns, colorations, or even shapes! The possibilities are endless, and as one gets more experience in breeding, one eventually learns about controlling which traits make it to the next generation and which ones don’t.

2 week old Swordtail fry
2 week old Swordtail fry

Assuming ideal tank conditions (74-82 degree Fahrenheit tank temperature, 5.5-7.8 pH, zero nitrites and ammonia), livebearers will readily breed. The dark spot near the belly of the female are actually eyes of all the babies ready to populate your tank! This spot will grow darker and darker until the mother is ready to give birth. Expect to have a few babies every 4-8 weeks.

In a densely planted tank, you normally don’t have to separate the babies from other fish, as they’d have plenty of places to hide in. If, however, the tank doesn’t have too many hiding places and is filled with lively, hungry fish, you’re going to want to place the pregnant fish in a separate breeding tank or an isolation breeder to give the small fish a chance to grow just enough so that they no longer fit the mouths of other fish in the tank. In any case, it’s best to have floating plants, as babies normally stay near the surface a few days after birth. If you choose to isolate the pregnant fish from the rest of the fish in the main tank, after the pregnant fish has given birth make sure you remove her from the breeding tank or isolation breeder so that she doesn’t end up eating her own babies.

Raising Fry

Newborn fry naturally have small mouths and therefore cannot eat pellets and other larger types of food you normally give to adult fish.

Guppy Fry
Guppy Fry

You’re going to need baby brine shrimp, specialized fry food, or finely ground flake food so that the fry will have something to munch on. In established, planted tanks, the fry will often feast on the biofilm that grows on java moss and other plant matter, which reduces the need for specialized food.

In about a month or two, the babies will be large enough to eat normal fish food and can also be placed back into the main tank.


You might have heard of advanced breeders talking about ‘culling’ certain fish. Culling refers to separating fish with undesirable qualities so that the next generation of fry will more likely contain desirable qualities. Remember that while you’d be able to purchase, for example, red guppies, it won’t be a guarantee that all the babies will turn out red. Some babies may have a duller, gray color, while some may have a vivid, striking new color.

If you don’t remove fish with different colors, then the generation of fry may have even more variations of colors. Eventually, you may end up with regular, dull guppies typically used as feeder fish. If you don’t mind getting different strains of guppies, then there’s no need to cull. Otherwise, you’re going to want to set up a ‘cull tank’ that contains all the fish with qualities different from what you’re going for.


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