How Many Guppies in a 30 Gallon Tank?

How Many Guppies in a 30 Gallon Tank?

Many people question the ideal number of guppies for a medium-size tank. However, a medium aquarium with 30 gallons of water has a large capacity to hold the maximum number of fish.

Moreover, guppies are the most favorable pet fish with a peaceful nature and look beautiful. Due to lower maintenance, they are suitable to grow in an aquarium with no previous experience.

How Many Guppies in a 30 Gallon Tank? You can add 15 to 20 guppies in a 30 gallon tank depending on their gender and the size of the particular species. Male fish are 1.3 to 1.6 inches long, while females are 1.3 to 2.5 inches long. Each inch of a guppy requires one gallon of water to survive. Therefore, you can add a minimum of 15 guppies of 2 inches in length in a 30-gallon tank. Add them in a 1:3 of males and females for better survival and reduction in stress. The number of guppies depends on the amount of water, gender, size of the aquarium, and the objects inside it. 

You can determine the number of fish in an aquarium through its capacity that provides apace to the maximum species to live inside.

What are guppies?

They are the freshwater fish that are commonly known as rainbow fish. Their tail is more prominent than their head which is small.

The male guppies have more beautiful colors in the long flag-shaped tails. These fish are active and you can easily keep them in a tank with a low maintenance effort.

Furthermore, they have a lifespan of almost 3 to 5 years, depending on their care. The male fish are 1.3 to 1.6 inches long, while the female ones are nearly 1.3 to 2.5 inches longer.

These male organisms have light bodies and weigh around 0.05 to 0.07g, and the bodyweight of females is 0.10 to 0.13g.

Furthermore, they are omnivorous species that can feed on the plants and small animals like mosquito larvae.

How many guppies can live inside a 30 gallon tank?

The number of guppies that can live easily together in a specific habitat depends on the amount of water present and the size of the fish.

There is a general rule about adding them to a tank which depicts that a single inch of the body requires one gallon of water to live.

So, you can determine the exact number that can reside inside the 30 gallons of water by their size.

An aquarium of 30 gallons can hold almost 20 to 22 male fish of an average size of 1.4 to 1.5 inches.

Moreover, the same quantity of water allows 15 to 18 female fish of an average size of 1.8 to 2 inches. A medium-size aquarium can hold 20 to 40 gallons of water and keeps 15 to 20 rainbow fish.

What factors determine the number of guppies in a tank?

Some factors help determine the exact number of guppies that you can add to a tank. You have to bring the size of the fish and the habitat under notice while choosing the same number.

Size of tank

The capacity of a tank determines the number of fish present inside it. Therefore, the aquarium size needs to match the weight of the water.

The wooden table supporting the aquarium should have a good weight holding capacity to tolerate the weight of the water, glass structure, and organism present inside.

The small aquariums are 12 to 22 inches long, while the medium and larger ones are 24 to 36 inches and 38 to 72 inches long.


The gender helps determine the size of the fish that you are going to add to a single tank. These male freshwater swimming organisms are smaller in length than females and take lesser space.

You can add fewer female fish than males because they require extra space to move.

Additionally, a combination of males and females is also a choice of many aquarium owners when they want to make it a breeding platform.

Amount of water

The extra amount of water allows more of them to be present in the tank. They can contain 0.5 to 80 gallons of water that provide a suitable space for 1 to 40 organisms.

Moreover, a medium-size aquarium contains 20 to 40 gallons of water that allow 10 to 20 females and 15 to 30 males of these aquatic organisms to live inside.

Presence of Plantation

The quantity of plantation and the pipes also determine the number you can add inside a tank.

Put a small number of plants on the sides of the aquarium to provide a larger surface area for swimming.

The excessive plantation in the habitat of these freshwater organisms creates a stressful situation with lesser oxygen and increased toxicity.

Therefore, you can add a small number of fish when the plants cover the free space.

How to maintain a 30 gallon tank filled with guppies?

It is not difficult to maintain a medium-size tank containing many aquatic swimmers.

However, you have to take care of their nutritional requirements, oxygen inflow, or the maintenance of proper living conditions.

Water hardness

You have to reduce the hardness of water by controlling the amount of magnesium and calcium ions dissolved in water.

Use driftwood to get control over the hardness and make it soft. You can filter the ware chemically, but driftwood addition is a suitable option.

While preparing the aquarium, you can put it that helps neutralize the water by releasing tannins. The color of water changes when pH gets lower due to these tannins.

water pH

These aquatic organisms are energetic and hardy aquatic animals that can tolerate the changes in the ph. The ideal water pH for these organisms is 6.9 to 7.7, close to the neutral range.

Moreover, they can live in slightly alkaline conditions but avoid a completely alkaline or acidic environment.

Quantity of nitrates

The different forms of nitrogen, like nitrates, are toxic for the guppies and inhibit their growth, so it is better to keep their quantity at a range of 0 to 0.5 ppm.

Their maximum nitrates tolerance limit is 0.5 ppm, which can otherwise have a negative impact on survival.

Furthermore, you can use an aquarium kit to test the number of nitrates in water to keep them as low as possible.

Less plants

It is better to avoid too many plants that can grow to several inches higher and interfere in the movement of these aquatic animals.

In addition, add a middle-ground plantation that can reach 5 to 9 inches at maximum. The long and thick plants interfere in swimming these freely swimming species.

Water Temperature 

Maintain an ideal temperature of around 73 to 80 degrees Fahrenheit that promotes a healthier environment and allows them to live happily in 30-gallons of water.

You can also use a cobalt heater rod to maintain the temperature when it fluctuates due to changes in the external environment.

Accordingly, it avoids changes in the internal environment of the tank due to fluctuations in the climate.

Proper oxygen inflow

A proper oxygen flow through water is essential to keep the guppy alive. You can use an agitator to allow water movement in case of a maximum number of fish in the aquarium.

Air circulation is essential to keep all organisms alive. You do not need to add a bubble but use an agitator for the continuous movement of water.

Food supply

A better food supply helps maintain a tank of 30-gallon water with many fish in it. Feeding them two times a day is sufficient to keep them healthy.

The younger ones require two meals in a day to grow rapidly, while you can feed the adult ones once a day.

Overfeeding is not suitable for their health and causes bloating because they start to eat as much food as you provide.

How many guppies can a large size tank hold?

A large tank contains 45 to 80 gallons of water and offers extra space for the guppies to be placed inside it.

45 gallons of water can hold almost 21 to 23 rainbow fish, while the one having 50 gallons of water inside increases the number of these freshwater organisms from 23 to 25.

Similarly, the 60-gallon water tank can afford almost 28 to 30 female and 32 to 34 male organisms.

However, their maximum capacity is almost 80 gallons, allowing 38 to 40 fish to move freely.

How many gallons do you need for 5 guppies?

You can consider the gender of guppies when you do not know about the amount of water and size of the aquarium that is ideal for their growth.

Every inch of these organisms needs one gallon of water to grow efficiently. Similarly, a single rainbow fish can reach 1.5 to 2 inches in length, depending on gender.

So, you need 5 gallons of water for the 5 male fish and almost 8 to 10 gallons of water for 5 female fish.

The female fish is 2 inches long and requires a 2-inch space, so the total volume of water reaches 10 gallons.

How many guppies should be kept together?

There is no specific limit to adding guppies to a single tank. You can choose their number according to the size of the aquarium.

It is better to prepare a 5-gallon tank and add a group of three guppies to it.

Moreover, you can consider an equal ratio of males and females to make it a breeding platform.

The perfect ratio between males and females is 1:3, which means females need to be 3 times more than males.

Add one male rainbow fish with three females to reduce the aggression and stress among these organisms.

Moreover, you have to keep the number minimum of three while designing an aquarium for the rainbow fish.

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