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Unless you have a single sex Platy tank knowing how to take care of Platy fry is an important part of keeping these colourful little fish. Platys breed freely in an aquarium so you’re likely to be looking after lots of little baby Platys at some point.
I adopted my first Platys from my son. He has a large community aquarium and his Platys were reproducing at such a rate that it made it impossible to keep them all. So to avoid overcrowding the tank, and making the tank environment unhealthy for the whole fish community, he rehomed most of the fry.
I took on 4 young Platy fish.
We thought I had 1 male and 3 females but that turned out not to be the case. The smallest of the 4 actually turned out to be another male. So I ended up with two of each sex.
Not the best ratio for Platys.
But they all did well in my small tank, reaching adulthood happy and healthy. The females, which are naturally larger than the males, obviously did particularly well because even for female Platys they are quite a size!
My small starter tank began to look crowded once the fish grew into adults so my son bought me a larger tank for my birthday.
I decided that the boys would stay in the starter tank as they were a lot smaller than the girls. I moved the girls into the larger tank and bought 2 more female Platys from my local Pet Store. Ones with different colouring from my original females to add a bit of variety to the aquarium.
By separating the males and females I hoped to avoid ending up with more fry than I could cope with.
Despite sharing a tank with the males for several months my females weren’t showing any signs of being pregnant when I moved them to their new home.
So imagine my surprise when a couple of days later I spotted a fry in the boys’ tank!
I’d been checking the girls tank for new arrivals just in case. But it didn’t occur to me to do a little ‘fry spotting’ in an all male tank.
I checked the tank thoroughly to see if there were any more babies hiding in there but there was just the one.
The tiny little thing looked like it had probably been born a few days before I’d moved the females into the larger tank.
While it’s not considered usual for only one fry to be born at a time it does happen. And after 4 weeks in the larger tank my pregnant female delivered a second batch of 8 fry.
I now had several Platy fry to take care of and I wanted to do it right.
My next step was to get myself some advice and I also did some research of my own.
In the process I’ve learnt some interesting and helpful stuff about Platy birth and caring for Platy fry.
So I’ve put together the answers to questions that are often asked about Platy birth and how to rear Platy fry successfully.
How Can I Tell If My Platy Fish Is Pregnant?
A pregnant female Platy usually behaves perfectly normally. Which means you need to look out for physical rather than behavioural signs to tell if your Platy is pregnant.
So what signs are there to look out for that tell you that your Platy fish is pregnant? Click here to read my article How Do Platy Fish Breed? for more information.
When we think of pregnancy the first thing that springs to mind is a swollen belly. After all, room needs to be made for offspring to grow. And it’s no different with the Platy fish. A pregnant female Platy will develop a swollen tummy, which is often angular in shape nearing the birthing, rather than just rounded out.
It’s not always that obvious though. My female Platys have always been chunky and rounded rather than sleek. I honestly didn’t notice any extra filling out to indicate pregnancy. And I do spend a fair bit of time watching my fish everyday. So I guess the natural shape of your own Platy might affect your ability to see a distinct tummy change.
Another sign that your female Platy is pregnant is that she develops a dark spot on her abdomen. The part of her abdomen that’s nearer to the anal fin. This is called a gravid spot. It’s not always possible to see the gravid spot if your Platy is dark in colour, but it’s there nonetheless.
Platy Fish Gravid Spot
The gravid spot on a platy fish is another indication that your female Platy is pregnant. The reason for this is that the dark colouration of the gravid spot is caused by the developing Platy babies (fry). The bigger the fry grow – the larger and darker the gravid spot gets.
As the fry get nearer to being born, and are pushing against the inner wall of the abdomen, it’s sometimes possible to see the eyes of the fry if mummy Platy is pale in colour.
Unfortunately pale coloured fish, both the males and females, can always look like they have a gravid spot. Because of their pale colouring you can see a ‘shadow’ of their internal organs, which creates a dark spot in the place where you would expect to see a gravid spot in a pregnant female. Both of my females and one of my male Platy have always had this dark spot on their abdomen.
Nonetheless, if your adult female Platy suddenly develops a gravid spot after spending time with the males it’s likely to indicate that the tank population is about to increase.
How Long Are Platy Fish Pregnant For?
If you’ve spotted signs that your female Platy is pregnant the next question you’re likely to ask yourself is, ‘When will my Platy fish give birth?’ The answer to which can help you to prepare for your new arrivals.
The simple answer is that the Platy’s gestation period lasts for between 24-30 days.
Judging when the birth will be can be a little tricky though. This is when spending time watching your fish each day reaps one of its many benefits.
One way to judge the approximate day that the fry will be born (it’s never going to be an exact calculation) is to note the date that you first see the gravid spot. Then count 24- 30 days. The fry are likely to be born within this time frame.
But as I say, it can be hard to judge it precisely. Particularly if your Platy is so dark in colour that you can’t see the gravid spot. Or, like my first Platy, they are pale and have always looked like they have a dark spot on the rear of the abdomen.
Another thing to look out for is a change in shape of the abdomen. It not only swells up but it can ‘square off’ as the female nears the birthing time. Squaring off looks exactly the way it sounds. The belly changes from an enlarged rounded shape to a more square shape.
You will probably also notice a change in the behaviour in your pregnant female Platy. She will start to isolate herself from the rest of the fish in your aquarium. She’s not being antisocial. She’s just looking for a quiet spot to rest undisturbed. And at the same time she’s finding a place that she feels is safe to give birth to her babies in.
So even if the gravid spot isn’t visible due to your Platy’s dark colouring, or it’s always looked as if it’s had a gravid spot because of it’s pale colour, there are other things to look out for that indicate that labour is imminent.
How Long Does It Take For Platy Fish To Give Birth?
The length of time it takes for a female Platy to give birth to all her fry varies quite a bit. The fry can be born all at once in fairly quick sucession. But they are often born in batches over a few days, or even weeks.
This will all depend on the individual female. Each of her pregnancies can be different and the fry can be produced at a different rate each time.
There are no hard and fast rules on this.
For example, there was around a four week gap between my single fry being born and the batch of 8 that arrived later.
During this time my mother Platy was kept in an all female tank so had not mated again with a male.
The unpredictability of how long it takes for all the fry from a single mating to be born is one of the reasons why it’s difficult to judge exactly how many fry you can expect.
However there are a few general guidelines that help to give you an idea about the possible number of new arrivals.
How Many Fry Can Platy Fish Have?
Just how many baby Platy fish can you expect to be born once your female Platy is pregnant?
Well it’s a staggering amount. Especially if you weren’t planning to breed your Platys. The female Platy can give birth to approximately anywhere between 8-20 fry at a time. Sometimes even up to 40 or more at one time.
You can see now why I said approximately. Because with the Platy you never can tell how many babies are likely to appear. You could get less or even far more.
Also, if you keep both males and females in the same tank continuously the fry can be born on an almost monthly basis.
That’s a lot of baby Platys to deal with!
The amount of fry born will depend on the female herself and the size and quality of the aquarium environment. I have been told that female Platys won’t breed in overcrowded or poorly kept aquariums.
But because the Platy is a prolific breeder there really is no guarantee of that.
How Big Are Platy Fry When They Are Born?
When Platy fry are born they’re really tiny in comparison to the adults. Which makes sense as the mummy Platy generally carries a large number of them at any one time and there’s only so much room to fit them all in.
On average a Platy fry measures around 7-8mm in length. Sometimes they can be even smaller than that.
Their tiny size can make them hard to see. Although after looking out for them for a few days your eyes usually find it a lot easier to spot them because you’re more aware of exactly what it is you’re looking for.
Using a magnifying glass makes tracking them down a little easier too.
Platy fry are born tail fin first and are also born to swim. They have a strong survival instinct and are good at finding places to hide in the tank. They can even hide under rocks and decorations and amongst the gravel at the bottom of the aquarium.
So even with good eyesight, and a magnifying glass to hand, the fry can still elude you.
Do Platy Fish Eat Their Fry?
The inbuilt ability of Platy fry to swim away at birth, coupled with their amazing ability to become almost invisible by hiding in the tiniest of spaces, is important for their survival into adulthood.
These tiny wriggling little fish are a lunchtime target for other breeds of fish in a community aquarium.
They are also likely to be eaten by their parents too.
Platy’s don’t have a protective instinct when it comes to their fry. Or anyone else’s fry for that matter. So the other Platys in the aquarium are likely to see the fry as a tasty snack. And it’s not just the other fish that will eat the fry. Even the mummy Platy may feast on her newly born offspring.
I know this sounds rather nasty but it’s just the way that Platy fish are.
I’ll never know if my single fry was an ‘only child’ or if it had siblings that didn’t manage to elude a hungry adult.
How Do I Save Platy Fry?
One way to give the fry the best chance of survival in a community tank, or even an all Platy tank, is to make sure your aquarium has plenty of hiding places within the plants and tank decorations. The hiding places need to be small. Too small for the bigger Platys and other adult fish to get into.
You can create hiding places in different ways. Dense leafy plants, whether live or soft artificial ones, make great places for the fry to hide in. You can use a combination of static and floating plants in your aquarium. Also both artificial and live grass or moss will make useful hidey holes for the fry.
Another way is to remove the fry to a separate tank until they are big enough to safely return to your main aquarium.
Or you can fit a breeder box/hatchery (like this one available on Amazon) into the tank at the top. It’s not advisable to put the pregnant female in the box though, as she will get distressed and may miscarry her young. But these boxes are another way to keep your fry safe until they are big enough to be introduced back into the main tank.
You also have the option of leaving things to nature and seeing how many baby Platys you end up with over time.
It’s up to you how you do it.
But it’s worth remembering that it’s best to be prepared if you want to save as many fry as possible.
When Can I Put My Platy Fry Into The Main Tank?
If you choose to remove the fry from the main tank there will come a time when you’ll want to put the fry back into your aquarium.
But just how big should fry be before you release them into the main tank?
The most important thing is go by the size rather than the age of the fry. Just like people fry grow at different rates. So counting the weeks after they were born will be of little use when it comes to deciding when to move them into the main tank.
The easiest way to judge when your fry are ready to go is simply to look at how big they’ve grown.
Then look at how big your other fish are. And more importantly how big their mouths are!
The fry need to be too big to be eaten by any of the fish in your aquarium if they are to stand any chance of surviving into adulthood.
Be aware though that fish often have an amazing knack of swallowing things that you’d assume they couldn’t manage to eat.
So give your baby Platys time to grow before moving them to their new home.
What Do Platy Fry Eat?
Baby Platy fish are as easy to feed as the adults are and will eat the same food too.
Just scrunch down your normal dry flake food into tiny pieces. It’s easy to do. You just scrunch it down in the palm of your hand into tiny powdery-sized pieces before putting it into your aquarium.
However, you can use powdered dry food that’s specially formulated for livebearer fish fry. These fry foods are enriched in protein and other important nutrients that help to promote healthy growth in young fish.
If you want to supplement your baby Platys’ diet with a little extra protein in the form of brine shrimp or daphnia it’s best to choose ones that are newly hatched rather than full size. They will be a lot easier for your Platy fry to get to grips with.
It’s important to avoid contamination in the tank from bacteria and parasites which can sometimes be introduced into the tank by live worms and shrimp. So frozen or freeze-dried protein is often the safer option when it comes to the meaty part of their diet. I’ve always gone for the dried option. But to be honest that’s probably more because I’m squeamish about feeding live foods rather than any worry about contamination.
It’s up to you though. If you have a supplier that you trust to sell you good quality ‘clean’ live protein for your Platys that’s great.
You can also top up the protein content of your Platy fry’s diet by feeding them a little boiled egg yolk paste.
Just mash a small piece of boiled egg yolk into a paste and drop it into the tank. This works best if you’re keeping your fry in a separate tank from the adults. Egg yolk paste is too fatty for the adult Platys so it’s not a good idea to add it to a mixed tank. And because the paste is messy you need to remove the leftovers quickly once the fry have finished feeding off it or you’ll end up with a cloudy, unhealthy aquarium
Platy fry also love to eat a range of vegetables. Courgettes (zucchini), cucumber, broccoli, peas and cauliflower are just a few of the vegetables that you can offer to your fry. You need to soften the vegetables by steaming or simmering, then cooling, to make them easier for your fish to eat. Any veggie additions need to be of an appropriate size for the fry to eat. You don’t need to add a big chunk. Just a tiny piece is enough for a treat and reduces the amount of food waste in the tank.
To avoid fouling the water remember to remove any uneaten vegetables from the tank once your fish have finished feeding.
Personally I’ve found that if the veg is well softened it’s a lot easier for the fry to eat them. My second batch of fry went crazy over the cooked broccoli floret that I offered them. Even though I thought the floret was really small it looked like a giant vegetable compared to the week old fry! They enjoyed it though and it was lovely to see them getting their first taste of fresh veg.
Fry are pretty tough so they do tend to manage well when it comes to getting their share of the food. But if you want to save as many baby Platys as you can, make sure some of the food you add to your aquarium at meal times is small enough for the fry to eat.
For more information about what you can feed to your Platy click here to read What To Feed Your Platy Fish.
How Long Does It Take For Platy Fry To Get Their Colours?
Some fry are born with more colour than others but this tends to be the ones that will grow to have a deep colouring as adults. An example of this is the fry born to my gold and black speckled female.
She must have already been pregnant when I bought her from the Pet Store because I kept her in an all female tank.
Nonetheless, along came the fry. Even at birth the black speckles on the fry were easy to see.
Generally though at birth Platy fry look almost transparent. And although their head and their eyes are more visible the tail end of their body is particularly pale. I always think that this combination of visible head and almost invisible tail gives them a tadpole-like appearance.
Because their lack of colour makes them difficult to spot it acts as camouflage and helps them to hide more effectively from the other fish in the tank until they are big enough not to be eaten. Okay, so that’s just my personal opinion. But being almost invisible is definitely a bonus if you don’t want to end up as someone’s snack.
So when do Platy fry get their full colours?
Getting their full colour takes a little time. At one month old you should start to see some colour developing on your fry. After two months the colour becomes more apparent. Between months three and four the colour should be vibrant.
Admittedly this is only a rough guide because each fry will grow in size and develop it’s colours at its own rate. But you’re likely to find that the rough guide isn’t too far off the mark.
Although, saying that. I do have a male Platy that was late in developing his colouring. When I first got him he was completely silver. There wasn’t a trace of any of the ‘blood orange’ colouring that his siblings were displaying.
At around 7 months old his fins got a peachy hue. Then over the next few weeks he developed that lovely vibrant ‘blood orange’ colouring on all of his fins and his body remained pale silver.
While he was always clearly a male he was a late starter when it came to taking an interest in the females in the tank. And it’s when he began to chase the girls around the tank, with mating in mind, that his colour came through and he became the most brightly coloured Platy in the aquarium.
How Long Does It Take For Platy Fry To Become Adults?
One thing I find odd about Platy fish is that they are sexually mature, and able to reproduce, a couple of months before they are considered to be adult fish.
Platys reach the reproductive age at around 4 months.
But they’re not considered to be full grown adults until they are 6 months old.
An adult male Platy grows to approximately 1.5 inches/3.81 cm. Females are generally a bit bigger at around 2.5 inches/6.35 cm.
As with all living creatures though, sizes can vary. I have a male Platy that’s barely just over an inch long including his tail fin, and a female that’s at least 3 inches long, tail fin included. She’s chunky too which makes her look enormous compared to all my other Platy fish.
What Can I Do With Unwanted Platy Fry?
Because Platy fish breed freely you’re likely to end up with a glut of fry if you keep both male and females in the same tank on a permanent basis. That’s not a problem if you have room for your ever expanding fish family.
But what do you do if you end up with more Platy fry than you can handle?
Here’s a few ideas about what to do with excess fry
- The first thing I would suggest is to separate the males and females and keep them in different tanks. That way once the female(s) have given birth to all the fry they are going to have from the initial mating there won’t be any more new arrivals. I know this doesn’t solve the problem of what to do with the existing fry but at least you won’t end up with even more to deal with.
- You can put the fry into the adult’s tanks, let nature take its course, and see if you can cope with the surviving number. I know it doesn’t sound nice but it’s natural for Platys to eat at least some of their own fry.
- Ask a local Pet Store if they will take the fry off your hands. They may pay you for them or take them for free.This will depend on the individual Pet Store though. Nonetheless, it will be a great help in rehoming them.
- Ask friends, family and neighbours if they are interested in rehoming the fry. There may be people you know that already keep fish or have been thinking about starting an aquarium.
- Advertise on social networking sites for people in your local area who would be happy to rehome your fry. You may even find some local fishkeeping enthusiasts that will take them.
- You could also ask local schools and educational centres if they would be interested in taking on some of the babies. Even offices and other businesses sometimes have a fish tank in the foyer so it’s worth asking around.
- If all else fails you can cull the fry. I’m neither condoning or condemning the practice of culling. I’m just pointing out that it’s another option if you can’t find an alternative solution. If your only option is to cull the fry have a word with your local Pet Store or Aquarium Dealer for some advice on humane ways to do it. Some of them may even offer this kind of service.
- Whatever you decide to do please don’t flush the fry down the toilet. They are likely to have a most unpleasant death. Even if they survive without being eaten by predators, or being poisoned by the sewage, it’s never a good idea to populate your waterways with species that are not native to your country. It can cause all sorts of problems with the natural balance of things.
Even if you weren’t planning to breed your Platy fish, finding babies in the tank is a lovely experience. Watching the tiny little fry grow is fascinating and rewarding. But if you’d rather not have more mouths to feed, or to rehome, then keep a single sex tank and enjoy caring for the the Platy fish that you chose to bring home.
