how long go guppy fry take to grow?

Guppies, also known as the rainbow fish, are among the most popular domesticated fish in America and worldwide. Amongst many other reasons, their ability to reproduce quickly has garnered them even more popularity.

Of course, the excitement of having new guppy fry eventually leads one to question how long they will take to grow fully. Therefore, we ask(in this article), how long do guppies take to grow?

In general, guppy fry takes around 5 to 6 months to grow fully. Female guppies have larger bodies than their male counterparts. They will grow 2.5 to 3 inches long in that period, while male guppies will grow to an average of 1.5 inches long. The measurement above has discounted the length of their tails.

There you have it; your new baby guppies will take some time to grow. It is to be noted, though, guppies start mating quite early in life. Female guppies will start reproducing at three months old. Though they reproduce early, it doesn’t symbolize their adulthood.

That being said, can guppies grow faster than that? If yes, how can that be achieved? By all means, please stick with me and find out more on this topic.

Can Guppies Grow Faster than Normal?

Is it possible for guppy fry to reach adulthood in less or more time? Well, like other living creatures, the conditions they are subjected to affect their growth curve significantly.

Guppy fry in perfect conditions will grow much faster compared to those in less suitable or worse conditions. If you want your fish to grow faster, you have to keep your aquarium in suitable conditions.

What are the Suitable Conditions for Faster Growth?

You have heard me talk about suitable conditions that will make your guppy fry thrive and grow faster. I am going to highlight them while providing enough info to keep you going.

Fish Tank Chronicles

First things first, you should keep older or parent guppies away from guppy fry. The older generation will not hesitate to eat the young ones even when fully fed. 

I recommend setting up a private tank just for the fry. Apart from keeping them safe, It is easier to take care of and monitor the growth of guppy fry in non-communal tanks. 

In commercial or habitual breeders, separate guppies by age, size, and gender (as soon as it is identifiable). You will reduce stress and competition for food amongst the fish, which eventually translates to higher growth rates.

Furthermore, guppies will start mating at three months old. Lots of energy that should have facilitated their growth are instead wasted in the mating process. Though it is impossible to separate guppy fry by gender immediately after birth, you should do it immediately when you can clearly define their gender.


Younger fish tend to need more than older ones. They need as much energy as they can get for their growth. 

It would be best if you fed guppy fry as much as 3 to 4 times a day. An automatic feeder will come in handy for aquarists who cannot consistently feed the fish at different times.

 The food diet they get must be of the best quality and varied. Varying the food types they get to eat ensures they have a steady supply of essential nutrients. 

You can adjust the feeding regimen accordingly as your fish grows older. That is to say, the amount of food they get will decrease as they grow.

Water Parameters

For guppy fry to grow well, you should effectively eliminate stress from the equation. There is no compromise about that. It won’t be easy to keep up with their needs, but at the end of it, all will be worth it!

The water parameters must be stable and always kept constant. You will have to do regular water changes to prevent even the slightest shift in cycle balance. I have seen fishkeepers do water changes once daily to keep the conditions in the tank suitable.

The water changes should also be of 10% to 20% per week maximum. Changing a larger percentage of your water will disrupt the equilibrium in your tank and trigger a mini cycle. Your fry does not need that. Keep them safe and thriving.

It is also important to keep the water flow slow and steady. A gentle filter will keep your water quality high, with the flow steady enough. Otherwise, most of your fish are going to be sucked up into the filters and end up dead.

In short, anything that can alter the set of conditions in your tank should be dealt with. This will incorporate cleaning your filters and substrate regularly to take out accumulated waste and debris.


It would help if you gave your fry ample water space/volume to live in. The space they get should not be too big or small…just enough. For instance, less than one-month-old fish need at least half a gallon of water. At one month old or more, 1 to 2 gallons of water is appropriate.

Larger spaces will mean more area for fry to explore and swim. The energy they waste roaming around in large open spaces is much better reserved for their growth. You can manage that by providing just enough space for each fry in the tank.

Final Thoughts

The growth of guppy fry is ultimately down to the care you give them. If you keep them in good conditions, then they will thrive like you want them to. Besides, with great care and attention, guppy fry tend to flourish and thrive.

The list above is not exhaustive of everything you can do to keep your fishing growing. However, the list is a foundation of everything else you will eventually add with more experience.