How Many Platies Should You Keep Together?


A lot of people who want to get into the hobby want to take care of Platies because they’re great beginner fish.  They’re hardy, they’re beautiful, and they’re very active. But the information regarding how many Platies to keep is confusing at best. You might be cautious of keeping too many if you’re a beginner, but Platies are very easy to care for.

A beginner hobbyist could keep 3 to 4 Platies together.  If you’re only keeping Platies in your tank, you can even start with 10 of them.

Do Platies Need To Be In Groups?

Platies are known to thrive together in an aquarium.

Platies are not really considered schooling fish.  They will not get aggressive if they’re alone or in small numbers like other schooling fish as long as there are no threats or bullies inside the tank with them.

Schooling fish are dependent on their numbers to feel secure, and Platies do not exhibit this characteristic.  Depending on the personality of your particular fish, they may appreciate or dislike being with other fish.

Are Platys Aggressive?

Platies are known as peaceful fish, able to live with a lot of other kinds of aquarium species without problems.  They’re not normally aggressive unless there are things out of the ordinary.

Platies are only aggressive if:

  • there isn’t enough space inside the tank
  • there is an improper male to female ratio.

Other than these, you should be fine raising Platies with other fish in a community tank or by themselves.

Are Platy Fish Fin Nippers?

Fights between Platies may happen from time-to-time over territory and females if there aren’t enough of these.

In the few occasions that Platies fight against other fish, fin nipping may happen.

To stop fin nipping, follow the proper Platy ratio and tank size suggestions.

Can I Keep A Single Platy?

Since a Platy doesn’t need to be in a group, it can definitely live alone.

Platies together in a a tank
Can I Keep A Single Platy?

There are numerous hobbyists who have kept a single Platy successfully without any problems.  Platies can live happily alone as long as it gets a healthy diet and clean water.

This is also probably the best kind of population control you can do with Platies, unless you already bought an adult female from the store.  It might’ve had contact with a male, and will end up giving you babies at home.

If you plan to keep only one Platy, a 10-gallon tank will suffice.  You can also add in other kinds of fish, or you can opt for Amano shrimp or some snails.

Can I Keep All-male Platies Together?

As mentioned, Platies are highly prolific breeders.

Without a female, male Platies will get aggressive towards one another due to their high energy and urge to breed. 

It is possible to keep all male Platies in a single tank only if you have lots of plants and other aquarium décor to serve as hiding places for them.  You should never keep them in a very small tank, too.

Can You Keep Just Female Platies?

Yes, keeping an all-female Platy tank is a great idea.  This is easier and better than having the all-male tank.

Unlike other freshwater fish where the female has a duller color than the male, female Platies display colors as bright and vivid as their male counterparts.  Female Platies are even a tad bit bigger than the males.

If you don’t want your Platies breeding, you can buy female Platies while they’re juveniles and not able to breed yet.  If you buy them as adults you might bring home pregnant Platies and have loads of fry to take care of sooner than you think.

How Many Male To Female Platy?

We can’t put equal numbers of male and female Platies or the males will pester the females constantly.

Platies are live bearers and these kinds of fish are all prolific breeders.  So in order to curb male aggression, Platies should have a male to female ration of 1:2 or 1:3 or one male for every 2 or 3 females.

How Can You Tell If A Platy Fish Is Male Or Female?

Platies are easy to sex visually since the difference between males and females are pretty obvious.

Male Platies have a long, pointed anal fin (the fin on the underside of the fish) called a gonopodium which they use to impregnate females.  On the other hand, female Platies have a triangular or fan-shaped anal fin.

Males also have longer dorsal fins than females.  The dorsal fin is the one on top of the fish as it swims.

Some people mistake male Platies to be females during their juvenile stage because of the lack of a gonopodium.  But as they mature, the differences become more apparent.

How Big Of A Tank Does A Platy Need?

Since an adult Platy grows to about 2.5 to 3 inches long depending on its breed, they should have enough space for themselves.

A group of 3 to 5 Platies should have a tank no smaller than 10 gallons because they’re very active and would need their territory.

How many platies can we keep in a tank?
How Big Of A Tank Does A Platy Need?

If you’re planning to keep male and female Platies together, get ready to have babies every month once the adults start to mature and breed.  If you want to keep the babies, you’ll need a bigger tank.  A heavily-planted 20-gallon tank at least would be good.  A bigger tank would even be better.

Just be aware that even though Platies are hardy, they don’t like soft water.  A dGH of 10-12 will be best for these, but that number can go up to 18dGH and they’ll still be okay.

Overstocking is definitely an issue if breeding isn’t controlled, and it is very hard to stop Platies from breeding.  If you have too many fish in the tank, you’ll have too much poop to clean and water changes will have to be more frequent.

If you want to keep that population low, a lot of hobbyists reduce feeding a little bit to let the adults eat the fry.  This “big-fish-eats-small-fish” behavior is normal in fish, but it is up to you what strategy you use.

Females will give birth every month or so.  And without separating the fry, you’ll get about a few survivors per month.  That should be enough population control for your 10- or 20-gallon tank.

If you do get batches and batches of fry that you want to keep though, you’ll have to separate them into a growout tank so they won’t get eaten.  These Platy fry can be sold to pet stores, given to friends, or sold to other hobbyists if you can’t maintain all of them.

Can Different Platies Live Together?

A single tank can have a Southern Platy and a Variatus Platy living together.  They will not harm each other.

You can even add in a Swordtail Platy to the mix as they are close relatives as well.  Beware though, that these might interbreed, and you’ll have a lot of babies in your tank.  Other than that, they’ll be one big happy, colorful family ready to give joy to you and other onlookers.

What Can Platies Live With?

Besides other Platies, there are also other fish and aquarium animals that they can live with.

If you’re keeping Platies in a community tank, they’ll thrive side by side with other peaceful species such as cory catfish, small tetras (such as neon tetras), rainbowfish, characins, bristlenose plecoes, dwarf gouramis, blue rams, ghost shrimps, amano shrimps, mollies, guppies, and even a Betta.

It doesn’t really matter if you get tank mates that are bottom, mid-, or top-dwellers, because Platies can stay at any level of the water column.  If on their own, you’ll find you Platies swimming everywhere: at the top, in the middle, or down below by the substrate.  They will adjust to their tank mates if a certain area is “claimed”.

This also means you can give Platies any type of food as long as they’re for freshwater tropical fish.  They are omnivores and can munch on dry, live, sinking, or floating food.

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