Mosquitofish vs Guppy: Key Differences Explained

Written by Hannah Ward
Published: July 2, 2022
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Mosquitofish and guppies are both small freshwater fish that are popular aquarium species. They are both extremely adaptable fish and can survive in many different conditions. Although small, these fish are actually known to play an important role in the fight against malaria as they prey on mosquito larva. However, although they share many of the same traits, they also have many differences too. So join us as we discover everything you need to know about mosquito fish vs guppies!

Comparing Mosquitofish vs Guppy

Guppies have a longer lifespan than mosquitofish.
Alternative NamesWestern mosquitofish, eastern mosquitofish, gambezi
Species – Gambusia affinis (western), Gambusia holbrooki (eastern)
Rainbow fish, millionfish
Species – Poecilia reticulata
OriginNative to the United States, introduced into many other countries, and often classified as a pestNative to Antigua, Barbados, Guayana, Suriname, Trinidad & Tobago, Venezuela.  Introduced to countries on every continent except Antarctica
HabitatShallow, standing, or slow-moving bodies of water – such as ponds and lakesSlow-moving rivers and streams with plenty of vegetation
SizeMale – Up to 1.6 inches
Female – Up to 2.8 inches
Male – 0.6 to 1.4 inches
Female – 1.2 to 2.4 inches
ColorDull grey or silver, occasionally with pale yellow or pale blue. Semi-transparent finsFemales – Grey
Males – Spots, stripes & blotches in almost any color
TailShort, in proportion with the body sizeMale – Large, rounded, colorful, flowing
Female – Shorter than the males with only a slight amount of color
DietMosquito larvae, insects, algae, zooplanktonAlgae, larvae, invertebrates, plant fragments
BehaviorPrefer to live only with other mosquito fishSocial – get along well with other fish
Reproduction16 to 28 day gestation.  2 to 6 broods during the summer20 to 30 day gestation. Reproduce every 30 days
LifespanUp to 1.5 years2 – 2.5 years

The 5 Key Differences Between Mosquitofish and Guppies

The major differences between a mosquitofish and a guppy are origin, tail, size, reproduction, appearance and lifespan.

There are two species of mosquitofish – eastern and western – and they are both native to the United States. Eastern mosquitofish are native to the eastern and southern regions – including Alabama, Florida, Pennsylvania, and Tennessee. Western mosquitofish are more widespread across the US and their range extends as far south as the Gulf Coast.  There is only one guppy species but around 300 different types – including the popular leopard and swamp guppies.

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Mosquitofish vs Guppy: Size

Animals With The Shortest Lifespan

Mosquitofish are slightly larger than guppies, with females reaching 2.8 inches long.


Although the difference isn’t huge, mosquitofish are generally slightly larger than guppies, with both fish exhibiting sexual dimorphism whereby the females are larger than the males. Male guppies are 0.6 to 1.4 inches long and females are 1.2 to 2.4 inches. However, male mosquitofish can reach lengths of up to 1.6 inches and females up to 2.8 inches.

Mosquitofish vs Guppy: Color

Easily the most distinctive difference between guppies and mosquito fish is their appearance. Guppies themselves have a different appearance between the males and the females. Female guppies are a fairly drab grey color with little to no color on their tails. However, male guppies are best known for their bright and vibrant appearance. They can be virtually any color which can be in any arrangement of stunning spots, stripes, or blotches.

Compared to guppies, both male and female mosquitofish are a dull grey color with semi-transparent wings. They occasionally have some pale brown, yellow, or pale blue color on them, but more often than not they are entirely grey or silver.

Mosquitofish vs Guppy: Tail

Another noticeable difference between the two fish is their tails. Mosquitofish have fairly short, rounded tails which are in proportion to their body size. In many cases, this is the same as female guppies, although female guppies do sometimes have a slight amount of color on their tail. However, male guppies’ tails – just like their color – are much more extravagant. Although male guppies’ tails are fairly rounded, they are long and flowing and have the same bright and colorful appearance as the rest of their body.

Mosquitofish vs Guppy: Social Behavior

Although both mosquitofish and guppies are both fairly laid-back fish, there is a difference in how they interact with others. Guppies are social fish, can live in schools, and get along well with other species of fish – even when sharing a tank with them. However, mosquitofish are generally anti-social towards others and prefer to live only amongst their own species when in a tank.

Mosquitofish vs Guppy: Reproduction

Multi color Guppy, Poecilia reticulata, on nature background

Guppies can reproduce every 30 days all year round – producing several hundred fry in a year.

©panpilai paipa/

The other really big difference between mosquitofish and guppies is their reproductive cycle. Guppies are known for being prolific breeders and can give birth to anything between 20 and 50 fry every 30 days right throughout the year – meaning that they can potentially give birth to several hundred in a single year.

Mosquitofish are nowhere near as prolific as guppies and although they too can produce many fry in each brood (between 10 and 100), they only reproduce during the summer months. In fact, mosquitofish only produce between 2 and 6 broods per year with the viability of broods being determined by factors such as water temperature, age of the female, and the amount of nutrients available. Research suggests that higher water temperatures (between 25 and 30°C) produce bigger brood sizes and a larger size at birth.

The photo featured at the top of this post is © Sarun Khaodara/

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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 mosquito fish from the same family group?

Yes, mosquito fish and guppies are from the same family group. They are both members of the Poecillidae family group which consists of many other small freshwater fish suitable for aquariums. However, guppies are from the genus Poecilia while mosquito fish are from the genus Gambusia.

Can mosquito fish and guppies breed with each other?

No, although they are from the same family group, guppies and mosquito fish are two very different species and are not able to breed reproduce together. If any accidental breeding did manage to occur then the resulting offspring would be likely to have several health problems and not survive for long.

Why are mosquito fish classed as pests?

Mosquito fish are classed as an invasive species in several countries – such as Australia and Spain. They were initially introduced to countries for the purpose of controlling mosquitoes and are now classed as one of the most widespread freshwater fish in the world. However, following their introduction, they are now threatening many species of native fish. They are threatening other fish species because they are aggressive towards them and frequently nip their fins. Additionally, as they prey on larvae, mosquito fish threaten the populations of any species which have aquatic larval stages – including frogs.

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