Livebearers Care Guide: Tank Conditions, Diet & Breeding

You might think that the name “Livebearers” is an odd one, but if you think about it, the name is appropriate. Livebearer refers to aquarium fish that carry their eggs inside the body, giving birth to live, free-swimming fry.

Even though only about one percent of all fish are live-bearing (viviparous), there are some distinct advantages to live-bearing births, so you may want to add some of these to your treasured aquarium. What could be better than watching the miracle of birth in your home aquarium?

Livebearers Facts & Overview


Care Level:Easy
Temperament: Peaceful
Color Form:Various
Lifespan: 5-7 years
Size: Over 2 inches
Minimum Tank Size: 20-30 gallons
Tank Set-Up:Freshwater with salt*
Compatibility: Peaceful community

*1 teaspoon per gallon; confirm safety for other tank inhabitants

Aquarium livebearers are generally from the Poeciliidae family. Common livebearers for your tank are guppies, mollies, platies, and swordtails. However, live-bearing fish are a varied group, and some other varieties outside the Poeciliidae family are:

  • Anableps (the four-eyed fish)
  • Goodeids
  • Halfbeaks
  • Mosquito Fish (also part of the Poeciliidae family)

And of course, we can’t forget the fish thought to be extinct but is doing quite well off the African coast: the Coelacanth pronounced see-la-kanth.

Because the fry of livebearers is larger than hatched fry, mortality rates are decreased and the care level is easier. This makes for a good fish for beginning hobbyists and those that want to teach their children about the phases of life.

Fun fact: Seahorses and pipefish are also livebearers, albeit male livebearers, since the males carry the eggs. Some cichlids incubate the eggs in their cheek (buccal area), a process called mouthbrooding.

In addition to the joy of watching fish enter the world, livebearers are valued because they are sturdy fish that can adapt to myriad habitats, and they have a beautiful coloring that adds a spark to your tank.

The Poeciliidae family contains what the retail aquarium world calls the “Big Four:” the guppies, mollies, platies, and swordtails that we mentioned before. The care guide at the beginning of this article details the care for the Poeciliidae. In this article, we’ll discuss the Big Four first and then spend some time exploring some of the other fascinating livebearers.

Fun fact: Many aquarium enthusiasts report that livebearers were their first fish; we’re not surprised. They’re a great beginner fish!

See Related Reading: Brackish Water Fish – A Complete Care Guide

Natural Habitat for Poecilid Livebearers

Native to the southeastern U.S, Mexico, Central America, northern South America, and many islands of the Caribbean Sea, Poeciliid livebearers are now found in nearly all tropical and subtropical parts of the world, inhabiting estuaries, lakes, pools, rivers, and streams.

Typical Behavior

Calm and collected, livebearers are peaceful members of the fish community (actually, it’s water compatibility more than the personality that makes the difference.)  The males are competitive and aggressive with each other, probably due to the fact that they are always attempting to mate.

Therefore, it’s a good idea to have 2 or 3 females for each male so that there is less fighting and so that the females are not harassed.

Livebearers jump when they feel threatened or scared, so make sure to keep the aquarium lid on tight.

Guppies – Guppies are calm and peaceful fish who swim around all day long. They’re pretty active, so if they’re hiding, they may be sick or stressed out. Male guppies shake their fins to try to attract the attention of females.

Mollies – Mollies are also pretty peaceful, but when they are around aggressive fish, they also become aggressive, so it’s vital to choose tank mates that have calmer personalities. Mollies are fun fish because they have distinct personalities.

Platies – Platies are also peaceful fish. Although they are not schooling or shoaling fish, they do prefer to be in groups.

Swordtails – Swordtail fish are active and peaceful. Like platies, they are social fish and like to be around other passive fish, whether it’s another swordtail or a different species.



The appearance of livebearers varies considerably between species and even within species, due to the myriad strains created by breeders.

Guppies – Guppies come in all different colors and shapes, although in the wild, the males are more colorful than the females. One of the reasons that there is a variety in guppy appearance is that breeders purposely make different strains for more variety in body and tail color. Guppies are generally small, with the males a little smaller than the females.

Mollies – The common molly has a flat body that’s tall in the middle and more narrow by the mouth. It has a caudal fin at the end that is similar to a large fan. Depending on the strain, this back fin is either colorful or transparent.

Mollies also have a dorsal fin that they can raise or flatten. Some popular types of mollies are Black, Sailfin, and Lyretail.

Platies – These fish have been interbred a lot, so they have a variety of colors that make them noticeable in your tank. Their fin shape also varies quite a bit.

Swordtails – With their unique and colorful fins, Swordtails also make a splash in your tank. Also bred to achieve color variety, swordtails are also known as Red Swordtails or Green Swordtails.

Habitat and Tank Conditions

There is some variation among the different species of livebearers, they prefer water that is somewhat hard and alkaline, and a wide temperature range between the upper 60s and the lower 80s F (18.9-28.3 C).

Actually, tap water fits the acceptable parameters for livebearers, so it’s not a big challenge to create an amenable habitat. It’s recommended to add a tablespoon of aquarium salt for every five gallons of water to mimic the brackish water in their native environment; just make sure the other creatures in your tank won’t be harmed by salt.

Aquarium Size

Livebearers can be kept in aquariums as small as 5 gallons depending on the number of fish you have, but the larger the aquarium, the more room they will have to swim and the happier and less stressed they’ll be. You never want to overcrowd fish.

Guppies – The general rule is one guppy for every two gallons of water, so it’s a 1:2 ratio: five guppies in a 10-gallon tank; 10 guppies in a 20-gallon tank; and if your guppy has babies, 50 guppies in a 100-gallon tank.

Mollies – You’ll need at least a 10-gallon aquarium to fit 4 mollies, and each additional molly needs 3 gallons, so 16 gallons would fit 6 mollies. Sailfins and some of the other larger mollies would need a 30-gallon tank for 4 fish.

Platies – Although they are small, platies need at least a 10-gallon tank.

Swordtails – One adult swordtail needs at least a 15-gallon tank; they’re not that large, but they are active swimmers.

If you want to add other fish, you will need a minimum of 29 gallons.

Water Specifications

Although they find hard, alkaline water in the wild, livebearers bred in captivity are adaptable to a variety of water conditions.

Livebearers have an ideal temperature range from the upper 60s to the lower 80s°F (18.9-28.3 °C) and a pH range of 7.0 to 8.4. Use a good filter that produces a moderate current and complete a 25% water exchange every two weeks.

Guppies – Guppies require a heater to keep the water in the 75-82°F (23.9-27.8°C). Their pH range is wide, from 5.5-8.5, but they prefer 7.0-7.2.

Mollies – Mollies like brackish water and need temperatures in the range of 72-78°F (22.2-25.6°C), a pH range of 6.7 and 8.5, and water hardness from 20-30 KH.

Platies – Ideal water temperatures vary by variety from 70-75°F (21.1-27.8°C), and all do well with a pH range of 6.8-8 and hardness level of 10-28 dGH.

Swordtails – Swordtails can tolerate a wide water temperature range of 65- 82⁰F (18.3-27.8°C), a pH between 7 and 8.4, and hard water from 12–30 dGH.


Livebearers do better in an aquarium with a moderate current, dark bottom, and lots of decorations. If you provide them with this environment, you’ll be rewarded with unstressed fish showing off their bright colors.

With livebearers, you are usually going to have two tanks: one for breeding and one for showing. The breeding tank should be substrate-free so that the fry can find the food. It also needs floating plants on the top as that is where livebearer fry like to hide.

Guppies – Guppies like live plants, rocks, and substrate. Guppies prefer the middle and top sections of the tank, so the type of substrate does not matter too much.

Mollies – Mollies need slower-moving water and a sandy substrate with rocks and plants. They can tolerate high hydrogen sulfide levels.

Platies – Platies will appreciate it if you mimic their natural habitat with gravel substrate and lots of plants.

Swordtails – Swordtails like moving currents with lots of plants and algae.

Tank Mates


Because they’re peaceful fish, they are easy to pair in terms of personality. Some compatible species consist of peaceful Barbs, Danios, Rasboras, Rainbowfish, and Tetras.

Guppies – Other members of the Big Four (Mollies, Platies, and Swordtails) are a good bet, as well as Corydoras, Gouramis, and peaceful Tetras. Compatible non-fish include African Dwarf Frogs and Ghost Shrimp.

It’s a good idea to isolate them from larger, more aggressive fish who may want to eat them. Aggressive barbs and tetras as well as Red-Tailed Sharks should be avoided.

Mollies – Avoid large and aggressive fish like Cichlids, and stick to peaceful fish like Cherry Barbs, Dwarf Gourami, and Harlequin Rasbora.

Platies – The rest of the “Big Four” are compatible, as are Characins, Corydoras, Gouramis, and Tetras. Non-fish friends are shrimp and snails. Platies should not be put in a tank with aggressive fish like Arowanas,  Cichlids, Tiger Barbs, and Wolf fish.

Swordtails –Swordtail fish are good tankmates for the rest of the Big Four, as well as Angelfish, and Corydoras.


Livebearers are omnivores that need a variety of foods to stay healthy and they do better with one or two small meals throughout the day — they enjoy grazing! Adding spirulina to their diet just might save your aquarium plants, too.

They’ll eat flakes, frozen and live foods.

Guppies – Guppies’ main diet should be fish flakes without fillers, supplemented with live or frozen bloodworms and shrimp. Cucumber, lettuce, and pea matter are also good choices.

Mollies – Supplement artificial flakes and pellets with algae, plants, and green vegetables from your garden or kitchen.

Platies – Although they are omnivorous fish, Platies have a preference for a herbivorous diet. Start with a flake food that doesn’t contain fillers and change it up with treats of bloodworms, brine shrimp, tubifex, and vegetables.

Swordtails – In addition to high-protein choices like flake food, brine shrimp, and mosquito larvae, Swordtails like a lot of vegetables and algae.


All aquarium fish are susceptible to disease, and livebearers are no exception. But there a number of ways to mitigate the possibility of disease entering your tank:

  • Maintain optimal water conditions
  • Change and test water frequently
  • Give them a variety of foods
  • Allow for abundant space
  • Minimize stressful situations
  • Quarantine new tank additions

Guppies – Because of their long tails, they are susceptible to fungus. Ich is also a common ailment, and visible by small white dots on their skin and the noticeable behavior change of rubbing against objects.

Fin rot, a condition in which the tail looks ripped, is another problem for guppies.

Medication can treat all these conditions.

Mollies – Mollies are susceptible to  “livebearer disease,” which is caused by substandard water conditions. They can also get ich and velvet. Signs of disease may be loss of appetite, inactivity, spots, wounds, and color changes.

Platies – Platies are robust fish, but they are prone to ich and fin rot like guppies are.

Swordtails – Swordtails can get ich, cottonmouth, dropsy, and fin rot. Again, keeping the tank clean and tested prevents many of these diseases from afflicting your fish.



As we discussed at the beginning of the article, livebearers get their name from the way they give birth: livebearers, like humans, give birth to live young, as opposed to laying eggs.

It is very easy to breed them, and sometimes you don’t even need to try and will suddenly notice that the female’s abdomen has grown in size or she has a large black spot near the back of her belly!

And since the males, as we mentioned before, are always looking to hook up, the aquarium hobbyist does not need to do anything special to create mating conditions. (Except, of course, to provide a higher female to male ratio so that the female is not stressed out by too much attention.

Distinguishing between males and females

  • Female anal fin is fan-shaped
  • Male anal fin is rod-shaped (gonopodium) and used to inseminate the female

Fun fact: Females store male sperm cells and produce multiple broods from single insemination.

The gestation period for livebearers is approximately four weeks.

Saving the fry

The fry, or baby fish, are liable to become a meal if the proper precautions are not taken.

  • Pregnant females can be moved to a hanging “breeder net,” which can decrease the likelihood of the fry being consumed by other tankmates.
  • Provide plentiful dense floating plants for the fry to hide from adult livebearers and make sure to feed fry and adults enough, as the adult livebearers will eat their young if they get too hungry.
  • Move the pregnant female into a separate breeding tank (5-20 gallons) just before she births the fry. After the female finishes releasing her young, move her back to the main aquarium, and leave the fry to get big enough.

Note: The breeding tank should include a filter, a heater, and floater plants, but no substrate.

Are Livebearers Suitable for your Aquarium?

Livebearers are a great addition to most tanks, and they are one of the few home aquarium fish that are easy to breed. They are colorful, fun to watch, and robust, making them a great beginner fish for children and adults alike make wonderful tank mates and are a great choice if you have the space for them.

Are Livebearers your favorite group of fish species? Let us know why in the comments below…

About Robert 394 Articles
Robert Woods is the creator of FishKeeping World, a third-generation fish keeper, and a graduate in animal welfare and behavior. He is also a proud member of the Association of Zoos and Aquariums, the Marine Aquarium Societies of North America, and the Nature Conservancy.

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