Livebearers FAQ


Ultimate Fish
Aug 26, 2003
Southern California
It was about time I did something here. :) Here is the beginnings of a livebearers FAQ. Please add anything you feel would be helpful. I will be looking for pics of males/females and gravid females.

Livebearing fish are called so because they give birth to live young (called fry), unlike most fish, which lay eggs. Livebearers include guppies, mollies, platies, swordtails and a number of other less well-known species.

Q: How do I tell the difference between male and female livebearers?

A: Adult male livebearers have a gonopodium (breeding tube) which is an adapted anal fin. This is the most reliable way of telling the sex of a livebearer. Males also tend to be smaller, and slimmer.

Q: How many males/females should I have in my tank?

A: If you want to breed livbearers, the best ratio is either 2 or 3 females per male. Males tend to pester a single female, and become aggressive. You can keep only males or only females in a tank. Females may come from the local fish store (LFS) already pregnant. Males may bother other fish, occasionally if there are no females, but it is not generally violent.

Q: Is my female pregnant?

A: The usual answer to this is “yes.” Even at a young age, if a female has been in a tank with a male, she is likely pregnant. Often they will come pregnant from the LFS. When pregnant, most livebearer females will have a “gravid spot” – a black patch behind their stomach. On black or dark fish you won’t be able to see this. A pregnant female will have a squarish look to her stomach area. The squarer she looks, the sooner she will give birth. You should also feed the pregnant female with high-protein live or frozen foods to have the best chances of healthy fry. Frozen or fresh bloodworms, brine shrimp, daphnia etc. are great foods for the expectant mother.

Q: When will my female give birth?

A: Most livebearers will give birth every 30 to 45 days. Sometimes they will “hold” fry for a while. Be patient. With some livebearers, water changes can help induce birth, so make sure to keep up with your weekly water changes. Mollies will often give birth with the addition of a little salt to the tank. Livebearer females can hold sperm. So even if you have no males around, she may have up to 4 batches of fry. Take this time to prepare for the fry by either getting a breeding trap or setting up a fry tank.

Q: My female gave birth! What do I do now?

A: The first thing you need to do is separate the adult fish from the fry. The best thing is to have a fry tank set up. A fry tank is usually a small, cycled tank with a sponge filter. Second best option is to catch the fry and put them in a breeding trap (available at your LFS), which keeps the fry in a separate container inside the main tank. If you have your livebearers in a community tank, and do not separate the fry, almost all adult fish will eat the fry. A heavily planted tank may give enough hiding places for a few fry to reach adulthood. Fish with non-conventional mouths like otos or plecos don’t usually eat fry. Healthy fry will not usually get sucked into the intake of your filter, but you can cover the intake tube with either sponge or clean stockings if the filter is very strong.

Q: What do I feed the fry?

A: You will need to feed your fry up to 5 times a day when they are young. The best food for livebearer fry is live baby brine shrimp. There are several DIY ways to do this, or you can buy a small hatchery from your LFS. You can also feed them special fry foods like Hikari First Bites or Liquifry for livebearers. Another option is to feed hard-boiled egg yolks that are crushed up, although this tends to foul the tank rather quickly. You can also feed the fry finely crushed flake, although this is the least nutritious option. To make it, put some flake in a sandwich or ZipLock bag and crush it with a rolling pin, the bottom of a jar or the back of a spoon. Fry have fast metabolisms, you will need to feed them often, and change water more often. Two or three water changes a week will keep your fry healthy and growing well. The better the food you feed your fry, and the better condition the water is, the healthier and faster your fry will grow.

A final note: Many livebearers are raised in intensive breeding conditions, leaving some livebearers unhealthy and generally weak. A lot of interbreeding and lack of natural selection has not been good for livebears, and it is not uncommon for females to die soon after giving birth or to have fry with genetic defects like bent spines.

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Forum Manager
May 16, 2003
Looks great Lotus! Consider yourself stickied ;)

You might want to add a question about the actual birthing process...we get a lot of questions "is my female finished giving birth" , "how many babies will she have" , "Will she have them all at the same time" , "Should I seperate her into a breeding trap while she's giving birth" etc

Sep 17, 2004
Visit site
I need help!!!!!!

I am getting conflicting reports on the proper ph level for angelfish on one site it says between 5.8 - 6.2 and on another it says between 6.2 -6.8 who can I call or email to get a definate answer on this I have mollies in my tank now and want to add angels but want to make sure my tank is properly set for them first thank you please let me know any info you may have or suggestions you can email me at thanks again


Large Fish
Dec 1, 2005
Omaha, Nebraska
ok i think im set. i put a tank divider in, took all rocks out from half, put 3 female platys and 1 male. put some salt in and tested water. i think im full ready for them.

Is there anything else i need to do?


New Fish
Dec 10, 2005
re: live bears. we just had babies.

Hi all.. new to fish. and of course we ended up with prego molly from the store.. she has just given birth and we had no idea until we saw the fry. question is it is midnight.. on sat evening. what can we do. to save some of the fry . i dont have a breeder nest.. not sure what that even looks like.. i dont have another tank either.. ..... is there anything we can do other than hope the fry make it..
.. we have two mollies in a large tank.. some plants but no where near what i have seen online .. and a few .. ghost cat fish. inthere too.. Any idea.
Thanks Peggi....