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Why Your Platy Fry Is Not Growing And How To Fix It!

With the demand for platies constantly increasing as the popularity of the fish species continues to climb, more and more people who already have platies are looking to try and breed their fish with a goal of turning a profit.

Now, it is extremely difficult for an amateur fish keeper to make money by breeding their fish so keep that in mind before you start breeding your platies but with there being so many people new to breeding their platies out there, we have noticed a number of them reaching out to ask about why their platy fry are not growing recently.

The most common reason that platy fry will not grow is due to a lack of suitable food in their tank as the majority of people try to feed their platy fry food that is simply too large for them when they should be using something like microworms for their fry.

Two less common reasons that your platy fry may not grow is due to being in a tank that has poor water parameters in it or too little water to encourage growth in the fish fry too.

Ideally, you will have a separate breeding tank for your platy fry to live in that is large enough for the fry to grow at a healthy pace but many people use a breeding box for their platies.

A breeding box is only meant as a temporary solution for your platy fry that need to be kept in your main tank to prevent the other fish from eating them and it is not large enough to encourage healthy growth in the fry after they are between one and two weeks old.

Why Is My Platy Fry Not Growing?

The most common problem that we see people make time and time again that slows the growth rate of their platy fry right down is that they will offer their fish fry an unsuitable food, often something that is too large just to fit in the mouth of the fry.

Second to that, problems with the water parameters that your platy fry are living in as well as the available space in the aquarium can also come into play and slow the growth rate of your platy fry too.

If you are leaving your platy fry to free swim in your main aquarium with minimal cover or hiding spots then the stress and anxiety of the other fish in the aquarium try to eat the fry can affect their growth rate too.

This is rare though as even a basic aquarium should have something that the platy fry can use as cover to feel safe but it can be a good idea to add some cheap fish fry hideouts or something like some breeding grass to your tank to offer additional cover and protection for your platy fry to help them grow quicker.

Most people who are new to fish keeping may not be checking their water parameters and although adult platies are quiet hardy, platy fry really do need stable, optimal water conditions to grow and thrive.

Getting a cheap water test kit should be enough to give you an idea of what type of parameters the water in your aquarium currently has and if there are any problems, you are able to quickly and easily correct them in most cases once you know whats wrong.

How Can I Make My Platy Fry Grow Faster?

The easiest way to help your platy fry grow faster is to make sure that you are feeding them a suitable food with microworms being one of the best initial foods for fish fry helping them grow at a healthy pace.

Making sure that your aquarium has optimal water conditions, plenty of space, and a low stress environment for the platy fry to grow is also ideal and can help to encourage a healthy growth rate in the fish too.

Depending on your overall setup and the plans for your platy fry in the future, a cheap 10 gallon aquarium can make the perfect breeding tank to offer an environment large enough for healthy growth that is also stress-free too.

You can put your pregnant platy into the breeding tank to give birth to her young and then remove the mother as she can and will eat her own fry with the platy fry being left in a safe environment in the breeding tank to grow at a fast pace.

As we mentioned earlier, a breeding box is a cheaper option than a totally separate breeding tank that can still offer you a number of advantages similar to a separate breeding tank for your platy fry.

Just keep in mind that a breeding box is not a permanent solution and you will usually have to let the fry out of the breeding box after a maximum of one month, usually two weeks to keep them growing at a healthy speed so adding some cheap fish fry hideouts to your aquarium once you let the fry out of the breeding box can help them avoid becoming an easy meal for one of their tank mates.

How Long Does It Take For Platy Fry To Grow?

Platy fry doesn’t grow as quickly as other species of fish even if their conditions are perfect and most people can expect to wait around six months before their platy fry are fully grown.

If there are problems in your aquarium stunting the growth of your platy fry then it can sometimes take around a year for your platy fry to grow to their full size.

This can sometimes catch people out who are new to breeding platies but are used to breeding other fish species as they expect the platy fry to grow just as fast as some of the other fish that grow at a rapid pace but this is not the case.

We would always recommend that our readers who are looking to breed platies pencil in a six month time frame from the day of birth until the fry are at their maximum size.

Please note that as your platy fry grow, you will have to change the food that you offer them too as microworms are usually only suitable for the first month or so.

As the fry grow you can start to integrate vinegar eels, bloodworms, daphnia, and various other food sources into their diet to help the fry maintain their growth pace and continue to grow quickly throughout the coming months.


That brings our article going over why your platy fry are not growing to an end. We hope that we have been able to help you better identify the potential reasons that your platy fry may not be growing at a normal pace but we would guess that the majority of our readers who are having problems with their platy fry growing are having the issue due to nutritional reasons. So many people try to feed their platy fry bloodworms and until the fry have grown to a certain size, they can’t usually eat bloodworms so have minimal nutrition to help them grow.