What to do With Extra Guppy Fry?

Guppies are very prolific at reproducing. The female guppy will give birth every 30 days and will deliver between 20 and 50 fry on average. You can multiply these values by the number of female guppies getting pregnant, which can often happen with 2 or more males in the tank.

In other words, if you’re not paying attention, your tank will fill up with guppy fry literally overnight. To prevent that, you want to control your guppies’ reproduction and remove the pregnant females from the main tank before delivery.

But let’s say you’re inexperienced or you simply had no time to handle the matter in time. Your aquarium is now teeming with freshly delivered little guppies swimming all over the place.

What now?

This article will provide you with 5 great solutions, teaching you what to do with the extra guppy fry.

Leave Them in The Main Tank

The first and most natural option that comes to mind is leaving them where they are. Mother Nature will take its course pretty fast. You see, female guppies don’t have a too well-developed maternal instinct. They are not known to care for their offspring, protect them, or raise them.

On the contrary, they might see them as prey and hunt them down. The same goes for male guppies. Guppy fry doesn’t have a problem with that in the wild since a pond or a river is large enough to allow the fry to run and escape. This doesn’t apply to a 10-gallon or even a 20-gallon aquarium, where space is limited.

If you didn’t plan on having any fry and you don’t really care about the whole situation, just leave them be. The adult guppy population will decimate their numbers fast. The few that will survive will grow to become adults, increasing your guppy population as a result.

The problem occurs when there are several females giving birth around the same time frame. This can lead to overpopulation, creating problems with oxygen levels, ammonia, and feeding issues. It will also increase aggression in adult guppies.

You can prevent this by removing pregnant guppies before delivery. You can quickly tell the males from the females since the females have the fuller and more protruding bellies. They are also less colored and slightly larger and longer than the males.

Simply move them into a separate tank or container, allow them to deliver, then move them back into the main tank.

Save the Fry for a Separate Tank

If you don’t have that many guppies, to begin with, a new batch of guppy fry may be just what you need. The female will usually deliver more guppies than you need to set up a new tank.

If you’ve decided to keep the fry, there are several things you need to do:

  • Separate the pregnant female – You can tell that the female is pregnant by its protruding belly. When the time comes, the female will seek hiding places or swim near the substrate, getting ready to deliver. You should remove the female from the main tank and place it into a different container with similar water and temperature conditions. The delivery will usually last a couple of hours, after which you can move the female back into the main tank.
  • Ensure the water quality – Your guppy fry requires the same water conditions as the adults. Make sure that the water in the temporary container shares the qualities of the main aquarium. These include temperature, oxygenation, and overall water cleanliness. Ensuring these parameters will allow your guppy fry to adapt to the conditions in the main tank a lot faster.
  • Stress the importance of feeding – There are two aspects I want to mention here. One would be to prevent overfeeding. Guppy fry will eat around 3-5 times per day, compared to adults who only eat 1-2 times per day. That being said, you can still overfeed the fry by giving them too much food at once. The unconsumed food will remain in the tank and decay, increasing the ammonia levels. The second aspect refers to nutrient intake. While guppy fry eats the same food as adults, they require a higher concentration of protein and fats. This dietary change is essential for their growth, allowing them to get bigger and more colorful.

You need to keep the fry separate from the main population for about 2 to 3 weeks at most. This will allow them to gain their strength and grow without having to contend with adults for space, food, and, pretty much, right to live.

Use Them as Food

If you’re more of a carnivorous fish lover and have set a tank specifically for meat-eating fish, the guppy’s prolific reproduction rate will come in handy. You can separate the female guppy from the main population, keep it in a separate tank until it delivers, and keep the fry as live food.

Or you can even feed them until they grow a bit bigger, choose the most handsome ones for your main guppy population, and save the rest for your carnivorous fish population. You should keep the latter, of course, separate from your guppies to avoid the impending carnage.

All carnivorous fish species love live food since hunting it down and exercising their natural killing instincts. There are quite a few interesting predatorial fish species that you can purchase, including:

  • Red-Bellied Piranha – This sweet-looking species seems innocuous at first glance, but looks have never been more deceiving. You will immediately recognize this fish’s dangerous nature by its red belly and protruding lower jaw, specific to piranhas. While it’s not as aggressive and dangerous as public opinion claim it to be, the Red-Bellied Piranha is a fierce fish nonetheless. You shouldn’t mix it with other species since the piranha is aggressive and territorial and will kill and consume pretty much anything that moves. Which, conveniently enough, includes guppy fry.
  • Pufferfish – The bulldog of the fish world has the sweet and cuddly looks to match its killer intent. Despite its seemingly harmless look, this is a predator in its own rights. It’s a highly territorial and aggressive species, ready to take on any intruders. Due to its size, the pufferfish will easily kill and consume adult guppies, let alone fry.
  • Asian Arowana – This is a mammoth among fish and a true killer. The Asian Arowana can reach 24 inches in length and will consume any other fish species around it. You will need a 250-gallon tank to house this beast and avoid placing any other fish in the tank that you want alive. It’s also worthy of mentioning that your guppy fry reserve is in no way fitting to satiate this monster.
  • Angelfish – The Angelfish is as cute as it is deadly. Although it’s only semi-aggressive and not really a threat to fish equal or close in size, smaller fish are not as safe around it. I recommend pairing the Angelfish with larger barbs and tetras to avoid aggression. If, for whatever reason, you wish to pair it with guppies, make sure that the Angelfish gets plenty of food throughout the day. This will minimize its aggressive behavior and will decrease the risk of targeting its tank mates.

Turn the Fry Into Profit

Guppies can come into a variety of colors, and wasting a unique pair with exquisite coloring is a capital sin. If your vividly colored guppies reproduce and the resulting fry look promising, sell them. The guppy market is always hungry, and you can make quite a profit if you know what you’re doing.

A decent pair can reach around $20, while a more unique one can get double or triple that. Having a consistent and regular supply of guppies for sale will turn profitable fast. Especially as you get loyal customers along the way, who will spread the word around the community.

Raising guppies for sale isn’t any different than keeping them as pets. The main difference here is probably the scale. You will no longer have 6-7 guppies to care for, but dozens. This means that your tank setup will require a different approach. Keep several 20 or 50-gallon tanks (or larger if necessary) and get all the equipment necessary.

This includes a high-end water filter, a reliable heater, an air pump, etc. These are necessary since you will most likely keep more guppies in one tank than you should. It will only be for short periods of time until you sell them, so the moderate overcrowding won’t get to upset them too much.

Enrich Your Guppy Community via Selective Breeding

If your guppies show very good genetics, it would be a great idea to save their offspring. You can get a separate tank for them or sell them if their coloring is highly appreciated on the market.

This is a tricky topic, however, since selective breeding requires more finesse than one might think. Before deciding on which guppy to keep, make sure that the parents don’t suffer from any condition. The bent spine syndrome is easy to detect, and it links to a variety of disorders, including fish tuberculosis.

This is a highly contagious disorder that can infect other fish, other animals, and even humans. You should also look for rugged fins or behavioral changes that may suggest an illness.

Once you’ve determined that the parents are in perfect shape, wait for them to breed and remove the pregnant female when it gets ready to deliver. Placing it in another tank and removing it once the fry arrive is a good strategy to prevent cannibalism, for which guppies are notorious.

You can then keep the resulting guppies or sell them if they exhibit unique coloring patterns. Special specimens can go for a lot of money under the right circumstances.


If you don’t want your guppies to reproduce, you should avoid adding any males into the tank. The bad news is that, in most cases, that’s not enough either.

Female guppies can store the male’s sperm for up to 10 months and use it to get themselves pregnant monthly. Some studies suggest that they can hold the sperm even longer than a year.

So, if your guppy females have mated with a male before purchasing them, they might get pregnant for a long time after purchase.

The good news is that even if you don’t want guppy fry, this article teaches you what to do with them. And, as you’ve read, there are some lucrative options to juggle with as well.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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