Guppy vs Betta: The Key Differences Explained

Written by Hannah Ward
Updated: July 10, 2022
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Bettas and guppies are both small but incredibly colorful freshwater fish. Their stunning and varied appearance makes them some of the most popular fish in the world as aquarium species. Given their colorful appearance, they can often be difficult to tell apart at first glance. However, there are a lot of fascinating differences between them. So join us as we discover everything you need to know about guppy vs betta!

Comparing Guppy vs Betta

Betta fish is generally considered brighter than a guppy.
OriginThailandNative to Antigua, Barbados, Guyana, Suriname, Trinidad & Tobago, Venezuela.  Introduced to countries on every continent except Antarctica
HabitatShallow water in swamps, marshes, and slow-moving streamsSlow-moving rivers and streams with plenty of vegetation
Size1 to 3.1 inchesMale – 0.6 to 1.4 inches
Female – 1.2 to 2.4 inches
ColorWide variety of solid colors, also many two-tone and rainbow colors.  Females are usually not as brightFemales – Grey
Males – Spots, stripes & blotches in almost any color
TailLong and flowingMale – Rounded and various lengths
Female – Shorter than the males with only a slight amount of color
MatingElaborate dance, spiraling around each otherQuick while swimming alongside each other
RespirationBreathes oxygen directly from the air as well as using gillsBreathes using gills
BehaviorAggressive towards others – including other bettasSociable, get along well with others
DietInsects, larvae, invertebrates, small fishAlgae, invertebrates, mosquito larvae

The 6 Key Differences Between Guppy and Betta Fish

The key differences between betta fish and guppy include size, reproduction, respiration, behavior, origin, and appearance.

There are 73 recognized species of betta fish. The most well-known species is Betta splendens which is commonly known as the Siamese fighting fish. Siamese fighting fish are some of the most popular aquarium fish but they are also a vulnerable species. Guppies are also commonly known as rainbow fish and millionfish. There is only one species of guppy – Poecilia reticulata – but there are around 300 different types with many being different variations of colors and patterns.
Let’s explore the differences in detail below.

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Guppy vs Betta: Size

An closeup of male tiger Endler guppy.

Guppies are much smaller than bettas.


One of the most obvious differences between guppies and bettas is their size, as bettas are usually much larger than guppies. Male guppies are usually 0.6 to 1.4 inches long, while females are between 1.2 and 2.4 inches long. However, although it depends on the species, bettas are typically between 1 and 3.1 inches long.

Guppy vs Betta: Appearance

Although bettas and guppies are both bright and vibrant, there are a few subtle differences in their colors. For a start, female guppies are a fairly drab grey color with little to no color on their tail. Male guppies can be virtually any color which can be in an arrangement of spots, stripes, or blotches.

However, while bettas are most certainly brightly colored, they can be a wide variety of solid colors, two-tone, or rainbow colors. In fact, bettas are generally considered to be the brighter of the two fish. Female bettas are also brightly colored but not as vibrant as the males.

Guppy vs Betta: Tail

The most distinguishable difference between guppies and bettas is their tails. This is because bettas have much larger and fancier tails than guppies. Male guppies have a tail that has a distinctly rounded appearance, even though the length itself can vary widely. Their tail is as bright and colorful as their bodies. Female guppies also have a rounded tail, but it is usually shorter than the males and has very little color on it.

Bettas’ tails and fins are quite easily one of their most stunning features as they are usually long, flowing, and brightly colored. The actual shape of the tail can vary widely, with their many different tail types being one of the reasons they are so popular as aquarium species. One of the rarest yet most revered is the fantail. Bettas with fantails have two caudal fins, which are fused at the top to create a fantail.

Guppy vs Betta: Reproduction

One of the main differences between guppies and bettas is how they reproduce. Guppies are known as “livebearers” as they give birth to live young. However, it is greatly debated as to whether they are ovoviviparous (eggs hatch inside the body) or viviparous. Despite this, their average litter size is around 30, although greater numbers can occur. Juvenile guppies are only 0.2 inches long when they are born but are fully formed and are able to swim away immediately after birth. Guppies are also incredibly prolific breeders, and females can produce a new litter every 30 days all year round! Not only that, but female guppies are able to store sperm for a long time after mating – meaning that they are able to give birth multiple times even if they have not been near a male.

The average clutch size of a betta fish is between 30 and 100, although up to 400 eggs is possible. Many species of bettas are “bubblenesters” whereby their eggs are protected in a nest of thick mass of bubbles. These nests are usually constructed by the male and are often made from air coated with saliva. Once the female has laid the eggs, the male chases her away and guards the nest while making sure that none of the eggs fall out. He also repairs the nest if necessary. Bettas are also prolific breeders, and females can be ready to lay eggs again after only a few weeks.

Guppy vs Betta: Mating

The method with which guppies and bettas mate is also different. Guppies mate very quickly while they are swimming alongside each other. Male guppies have a modified anal fin which is long and pointy and has small hooks on it. This is called a gonopodium and is used as a copulatory organ to inseminate the females.

When bettas are mating they perform an elaborate mating ritual which is like a dance. This is where the male and females spiral around each other during mating and is known as the “Nuptial Embrace”. Prior to the Nuptial Embrace, the male shows his interest in the female by spreading his fins and twisting his body around in a dance. The Nuptial Embrace is the act of spawning and involves the male wrapping his entire body around the female.

Guppy vs Betta: Respiration

Red Animals - Siamese Fighting Fish

Bettas can breathe oxygen from the atmosphere as well as using their gills.


The most fascinating difference between guppies and bettas is how they breathe. While guppies breathe through their gills, bettas breathe through their gills, and they breathe oxygen directly from the air too. Bettas come to the surface of the water and breathe atmospheric air using an organ known as the labyrinth. This allows the oxygen inhaled from the air to be absorbed into the bloodstream. This unique feature allows them to survive in low-oxygen environments. It also means that they are able to survive out of water for short periods of time so long as they are kept wet. Fish with a labyrinth organ is known as anabantoids or labyrinth fish.

The photo featured at the top of this post is © Mr. Witoon Boonchoo/

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About the Author

Hannah is a writer at A-Z animals where her primary focus is on reptiles, marine life, mammals, and geography. Hannah has been writing and researching animals for four years alongside running her family farm. A resident of the UK, Hannah loves riding horses and creating short stories.

FAQs (Frequently Asked Questions) 

Are guppies and bettas from the same family group?

No, guppies are from the Poecillidae family group which consists of many other small freshwater fish suitable for aquariums – such as platys, mollies, and swordtails. Bettas are from the Osphronemidae family group whose members are known as “gouramis”. Fish in this family group are all native to Asia and all show some kind of parental care to their young – such as the nurturing of the eggs in the bubblenest by bettas.

Can bettas and guppies live together in the same tank?

Although it is possible for guppies and bettas to live together in the same tank it is not advisable. This is because bettas can be incredibly aggressive towards other fish and will eat the guppies if given the chance.

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