Platy vs. Molly: The Ultimate Comparison in 2024

Platy and molly fish are two freshwater species that are so similar that it can be hard for most aquarists to tell them apart. Despite their similarities, however, rest assured that these little creatures are unique in their own way. You may then wonder how platies and mollies compare.

Platies and mollies share similar family origins, personalities, food requirements, water conditions, and breeding habits. They, however, show some contrast in shape and size. Mollies are generally larger with flattened and elongated bodies, while platies are smaller with shorter and rounder bodies. 

I’ll compare and contrast the platy vs. molly fish in this article. Read on to learn more about each fish and how they differ. By the time you get to the end of this post, you’ll have made the most appropriate choice as per your preference.

Platy Fish

Platy fish are popular among aquarists – beginners and veterans – because of their peaceful nature, vibrant coloration, and low maintenance.

This freshwater fish belongs to the Xiphophorus genus and is also a member of the Poeciliidae family alongside mollies, swordfish, and guppies. They’re native to the east coast waters of Central America and Southern Mexico.

Basically, two species of platy fish exist. The southern platy fish (Xiphophorus maculatus) and the variatus platy (Xiphophorus variatus). These species are often interbred with each other or the swordtail species, resulting in hybrids of various colors available in the aquarium trade today. 

Below is a quick summary of the platy fish. 

Types of Platy Fish

As I mentioned earlier, there are a bazillion varieties of platies in the market thanks to interbreeding. These hybrids have unique qualities, which most hobbyists and collectors adore.

Some varieties are rarer than others and may not be found at your local pet store. You may need to consult an expert breeder to get these unique specimens.

And since it’s impossible to go over every single variety, here are a few popular types of platy fish. 

• Mickey Mouse Platy: This fish gets its name from the three spots near the base of its tail that resemble the head of the famous Disney character. Mickey Mouse platies come in several colors, mostly yellow, red, or orange. It is one of the rare varieties. 
• Gold Red Platy: This fish gets its name from its gradient coloring. The light gold color on the front half of its body gradually turns to deep red towards the rear half with a gradient sunset. Gold and red are the most common color combinations, but you can also find blue and green variations of this fish.
• Pintail Platy: The Pintail platy is known for its unique tail. It has an elongated midsection resembling a pin. They come in numerous hues and pattern combinations. 
• Red Wag Platy: Also called the red wagtail, these fish are eye-catching. Their bodies are fiery red, with jet-black fins and tails. Some may have black coloring near the mouth or tail end. 
• Neon Blue Wag Platy: The Neon Blue Wag platy is another rare variety. Its body is covered in blue with jet-black fins. The color intensity can range from pale sky blue to neon blue. 
• Rainbow Platy: This colorful fish appears in shimmering rainbow colors under the aquarium lighting. The shades may appear in patches or fade into each other. Like wagtails, Rainbow platies have black fins. 
• Dalmatian Platy: This wildly popular platy fish imitates the appearance of a Dalmatian dog. You can quickly identify Dalmatian morphs by their white base color and black spots. Some may have a few spots, while others may have a boatload.

Find Out: How Long Does It Take a Molly to Give Birth?

Physical Characteristics

Color Varieties

As you’ve seen from the various types of platies described above, these fish come in a vast array of colors and patterns because they’ve been extensively bred. More so, breeders are constantly producing morphs with new colors and patterns. 

Standard colors observed in platy fish include the following:

• Black 
• Blue (neon blue, sky blue)
• Gold/yellow (golden, marigold, sunburst, sunset)
• Red (blood red, brick red, coral red, velvet red)
• Green
• Brown
• White

The different color patterns available include the following:

• Tuxedo ( front half of the body can be any color while the rear half is black)
• Wag ( body can be any color, but the fins are black)
• Variegated (body can be any color but splashed with black spots)
• Rainbow (a combination of more than three colors)

It’s also noteworthy that the colors of wild platies are not as many and brilliant as their selectively bred counterparts. They usually come in shades of brown, beige, and dull orange. 

Size and Shape

When you observe a platy fish, you’ll notice a relatively short and flattened body with a unique triangle-shaped head and forward-facing mouth. The mouth creates a focal point from which the body expands to the midsection (widest point) and then declines a bit before hitting the fan-shaped tail section. 

And while platies are usually small, their sizes vary based on gender and species. 

Female platies are generally bigger than male platies, sometimes up to an inch larger! Their midsections also tend to be wider than their male counterparts. They can grow between 2.5 to 3 inches, while the males reach a maximum of 2 inches. 

Regarding species, the southern platy is slightly smaller than the variatus platy. You’ll also find selectively bred dwarf variants that don’t exceed 1 inch (2.5cm) in the market. 

Habitat and Tank Requirements

Ideal Tank Size

Thanks to their small sizes, platies do not require an enormous tank to stay happy. A group of about 4 to 6 platies will do just fine in a 10-gallon tank. 

The rule of thumb is one inch of fish for one gallon of water; you’ll therefore want to increase the tank by 2 gallons per every additional platy.

However, bigger tanks are always appreciated, as platies are very active creatures. They love exploring their surroundings, so a larger tank provides ample space to swim and play. 

Water Conditions

Wild platies are known to inhabit rivers, marshes, and ponds. These slow-moving waters are often warm, moderately hard, and with dense vegetation. 

And while platy fish are hardy and adaptable to various environments, they thrive in aquariums with similar water conditions to their natural habitats. 

For this reason, always ensure your tank’s water parameters match the following readings.

• Water temperature: 70°F – 77°F (21–25°C)
• pH levels: 6.8 – 8.0
• Water hardness: 10 – 28 dGH

Platies also prefer plants as hiding spots, so remember to add several and leave enough space for swimming. 

Behavior and Temperament

Compatibility With Other Fish

Platies are excellent team players. They are peaceful, social, and friendly towards other fish, making them great for community tanks.

The only downside is slight aggression within the species. Sometimes, the males will get rough with each other, but it’s rarely a significant cause for alarm. 

Also, since they love to breed, the female platies might face problems if the males outnumber them. The males will likely chase, nudge, and push them around a lot, trying to get their attention. 

Thankfully, you can fix this by maintaining a ratio of one male to two or three females in a group. 

Overall, platies are easy-going and can make great tank mates with other peaceful, similar-sized fish. These include mollies, guppies, tetras, danios, swordtails, corydoras, shrimps, and snails. 

Breeding Habits

Platies are prolific livebearers. This means the females do not lay eggs but give birth to free-swimming babies. 

They breed readily when the diet and water conditions are right. 

Female platy can give birth to up to 40 fry at once. With a gestational period of 24 – 30 days, they can reproduce nearly every month. 

That’s a staggering amount! Particularly if breeding platies wasn’t in your plans. 

Interestingly, platies lack protective instincts and will likely see the babies as a tasty snack. Even the mummy may feast on her newborns. I know it sounds horrible, but that’s their nature. 

If you wish to save as many fry as possible, you’ll want to create lots of hiding spots in the aquarium using live and artificial plants. Alternatively, you can transfer the fry to a separate tank and nurture them from there. 

Molly Fish

Mollies are among the most renowned fish species in the aquarium trade, thanks to their variety of beautiful colors, ease of care, and adaptability to different tank setups. 

Their peaceful and social nature makes them excellent for freshwater community tanks. Mollies are also not picky eaters. As such, they’re fantastic at cleaning aquariums by constantly gobbling up leftover food. 

Wild mollies thrive mainly in freshwater habitats, sometimes venturing into brackish environments throughout North and South America. 

While they can adapt to powerful sea waters, it’s not their natural habitat. Mollies love slow-moving tropical rivers with lush vegetation. 

Here’s a quick overview of the molly fish.

Types of Molly Fish

The number of molly fish hybrids with varying shapes, colors, and fin types is incredible. Below are some of the most popular types. However, you’ll have to dig more if you want something rare, as you might not find them at your local pet store. 

• Black Mollies: As the name suggests, these mollies are majorly covered in black scales but can have splashes of other colors. They’re also referred to as Common Black Molly.
• Balloon Mollies: These fish get their name from their signature body shapes, making them appear overweight with bulbous bellies. Balloon mollies come in diverse colors and patterns. 
• Sailfin Mollies: These fish are larger than other mollies. They’re also identified by their long, flowing dorsal fins that elongate to the base of the tail fin. Like balloon mollies, they’re found in many colors.
• Dalmatian Mollies: These fish are covered with a white base color and black spots. They closely resemble the markings of the Dalmatian dog, thus, the name. 
• Lyretail Mollies: These mollies feature caudal fins with extended top and bottom ends, creating a fork-like appearance. They’re primarily available in black, white, and yellow. 

Physical Characteristics

Color Varieties

Mollies come in a wide array of dazzling colors and patterns due to interbreeding for over a century. These colors include black, white, silver, red, yellow, chocolate, orange, and golden varieties. 

For instance, the black molly has a unique velvety black color, but you can find others covered with splashes of orange or yellow at the fins. While some mollies come with solid single colors, you’ll find other varieties with combinations such as:

• Black and white with gold speckles
• Platinum and gold
• Bright yellow and black
• White, black, and yellow
• White and orange, etc.

Size and Shape

Most varieties have a similar appearance to the Common black molly. They feature laterally flattened and elongated body shapes with slightly arched backs. They also have triangular-shaped heads with upward-facing mouths. 

You can differentiate a male molly from a female by its body size and the shape of its anal fin. Males are generally smaller and feature pointy anal fins. On the other hand, female mollies have broad and fan-shaped anal fins.

Most molly varieties grow up to 3 inches on average. The sailfin molly, however, can grow up to 5.5 inches on average. Some might even reach 6 inches. 

Habitat and Tank Requirements

Ideal Tank Size

The ideal tank size will depend on the adult size and the number of the selected molly species. 

Based on the 1:1 ratio, an average 3-inch adult molly fish will need three or more gallons of water to survive. That’s to say, a 10-gallon tank will comfortably accommodate up to 3 average-size mollies.

Needless to say, you’ll need a bigger tank for a larger group of mollies. 

For slightly bigger varieties, such as sailfin molly, experts recommend a 20-gallon tank minimum. This size recommendation suits up to three sailfin mollies, even though getting a bigger tank is never wrong.

Water Conditions

As I mentioned earlier, mollies are naturally freshwater fish. But since they are very adaptable, they can survive with some salt, also called brackish water. 

The exact water conditions may differ depending on the species you choose. But generally, mollies thrive in warm waters between 75 to 80 degrees Fahrenheit. As such, you may require an aquatic heater to stabilize the aquarium temperatures. 

They also prefer a neutral PH ranging between 7.5  and 8.5 and 15 to 30 KH water hardness. 

Behavior and Temperament

Compatibility With Other Fish

Generally speaking, mollies are peaceful creatures and can easily get along with other community fish, mainly of similar sizes and tank requirements, such as tetras, platies, danios, barbs, loaches, dwarf cichlids, and cory catfish. 

However, they are active and love pecking at things to determine whether they are edible. So, putting slow-moving, long-finned, or smaller aquatic animals together with larger mollies may not be the best idea. Doing this might encourage predation. 

Also, larger or aggressive fish may not be the best tankmates for your mollies, as they may get bullied or eaten up. 

Breeding Habits

Like platies, mollies are livebearers. They hold fertilized eggs within their bodies for 40-60 days until they hatch and release them fully formed into the water. 

Mollies breed a lot! And it often happens without human intervention. With at least one male and a female in your tank, you’ll have hundreds of fry within no time.

You’ll want to breed your mollies in a controlled environment if you’re looking to increase the babies’ chances of survival. 

Unfortunately, this species lacks parental instincts – most adults will try to eat the babies. 

For this reason, you should provide lots of dense aquatic plants as hiding spots for the fry.

Platy Vs. Molly Fish: Head-to-Head Comparison

It can be challenging to tell a molly from platy as they share many similarities. A keen eye, however, will notice some subtle differences between them.

As we’ve already covered the individual fishes extensively, we shall now point out their similarities and differences to help you make an informed choice. 

Similarities Between a Molly and Platy Fish

Platies and mollies can confuse amateur aquarists as 

• Both belong to the same Poeciliidae family. 
• Both have social, peaceful, and friendly personalities, making them excellent choices for community tanks.
• Both require low-level maintenance and are perfect for beginners.
• Both are prolific livebearers.
• Both are omnivores with the exact food requirements.
• Both come in a range of colors.
• Both are similarly sized.

Differences Between a Molly and Platy Fish

As shown in the table below, Molly and platy fish slightly differ in origin, appearance, and diet behaviors.

Considerations for Choosing Between Platy and Molly

Both the platy and molly fishes are fantastic additions to your community aquarium. They’re peaceful, easygoing, easy to care for, and come with attention-grabbing colors.

So it can be pretty challenging to choose between them – both are great in their own right!

Perhaps the criteria to use is their physical attributes, as they contrast sharply in size, shape, and color. 

All in all, it all trickles down to personal taste and experience. But if you still can’t decide what to choose, why not take both? 

Can Platies and Mollies Live Together? 

Yes. Platies and Mollies can live together. They make excellent tank mates since they both have peaceful and friendly personalities. 

Moreover, both species are livebearers and share almost similar natural habitats. Their water requirements overlap, so they’ll thrive in the same aquarium. 

And since you can also feed them similar food items, it won’t be a challenge to meet both of their needs concurrently.