Here are the tank size recommendations for guppies:
| Tank size (gallons) | Number of guppies |
| 5 gallons | 3 |
| 10 gallons | 5 |
| 20 gallons | 10 |
| 25 gallons | 12 |
| 30 gallons | 15 |
| 40 gallons | 20 |
| 55 gallons | 23 |
| 75 gallons | 37 |
| 90 gallons | 45 |
The rule of thumb is to keep at least three guppies in a 5-gallon tank, which is the smallest tank size for these fish. You can stock up to 5 guppies in a 10-gallon tank, 10 guppies in a 20-gallon tank, 15 guppies in a 30-gallon tank, 27 guppies in a 55-gallon tank, and 37 guppies in a 75-gallon tank.
Guppies are the most widely distributed pet fish worldwide. They are beautiful and pretty easy to care for. Overcrowding guppies can have a negative impact on their health and happiness. I’ve discussed the signs that your fish tank is overcrowded and recommend some tank sizes and the number of fish to keep in each tank.
Guppies like to spend most of their time at the upper levels of the tank. So, a wide tank would be the best instead of a narrow-deep tank.
Tank Size Recommendation for Guppy Fish
An overcrowded tank can lead to breathing complications in fish and can encourage the quick spread of diseases in your aquarium. Keeping the correct number of guppies in a tank is good for the guppies’ health. The tank size varies depending on the number of guppies you want to keep and the reason for keeping them.
Generally, you need one gallon of water for every one inch of a guppy. The minimum tank size for breeding guppies is 30 gallons. The ratio of females to males should be 2:1 to avoid overpopulation. But when keeping for decorations, I recommend keeping only male or only female guppies.
Let’s get right into it.
How many guppies in a 5-gallon tank?
A 5-gallon tank is the minimum tank size recommended for keeping guppy fish for decoration. Keep three male or three female guppies in a five-gallon tank. Guppies are colorful fish, but the male guppies tend to be more colorful than the females. Schooling allows guppiesto play, keep each other company, and ward off predators in the aquarium.
A 5-gallon tank is enough to keep the guppies from birth till adulthood when they are grown to 2 inches long. Another good thing about this tank is that it’s small. Therefore, it is easy to clean and maintain, unlike some large and heavy tanks.
Care for guppies in a five-gallon tank involves removing the guppies gently from the tank and placing them in a container with the original water solution. Cover the container so the guppies don’t jump out of the water.
Remove all the water and use a clean cloth or a paper towel to wipe the tank gently and remove all the dirt. Do not use concentrated soaps or chemicals to wash the tank as it can affect the water chemistry and make your guppies weak. Some chemicals could even kill the fish. Put back your fish and top up the water.
Put the five-gallon tank on a living room table or at the receptionist of your office. Do not place the guppies in direct sunlight because five gallons is more susceptible to temperature changes. High temperatures can remove oxygen in the water and encourage the growth of algae.
10-gallon tank
A 10-gallon tank is suitable for aquarium beginners who want to keep guppies. A 10-gallon tank is large enough to accommodate up to five guppies as it will provide enough space to swim. It provides an increased surface area for oxygen.
A 10-gallon tank is not recommended for breeding guppies because it’s still quite small to accommodate adult guppies and guppy fry. The fish would compete aggressively for space and oxygen. Besides, it is difficult to add decorative substrates and plants to a ten-gallon tank without reducing the number of fish to keep in the tank.
Maintaining a 10-gallon tank is also quite easy. Remove the fish and place them in compatible water conditions inside the tank. Using a clean cloth, clean the tank both inside and outside. Do not use chemicals to maintain the ph levels and keep the fish inside the tank. Change 100% of the water and place the guppies back inside the tank.
20-gallon tank
A 20-gallon fish tank can accommodate up to ten guppies. The guppies will swim freely and play without knocking and injuring each other. The oxygen supply inside the water is also steady, keeping the guppies active and healthy.
If you want to breed guppies for the start, use a 20-gallon tank. In that case, there should be more female guppies than male guppies in the tank. Start with one male and two female guppies or more in the tank. As the guppies reproduce, their population will double in just two months. At that point, you will need a larger tank for your guppies.
With a 20-gallon tank, you can decorate the tank with some aquarium plants, rocks, and pebbles to provide good hiding, playing, and breeding spaces for guppies. Make sure the substrate you add inside the aquarium has no sharp edges that can bruise and tear the fish.
25-gallon tank
There is no significant difference between a 20-gallon fish tank and a 25-gallon tank. However, the five additional gallons can hold some extra guppies. Keep between 10 and 12 guppies in a 25-gallon tank.
A 20-gallon tank is suitable for breeding guppies, but you will need a bigger tank to accommodate the young guppies. Otherwise, the fish will be overpopulated, and the water will not be able to provide adequate oxygen for all the guppies. Overpopulation also destroys the water quality and lowers the lifespan of guppy fish.
Decomposing fish food leftovers also contribute to ammonia build-up in the aquarium and can kill all guppies in the tank quite fast. Change 50% of the water every week and wipe out any dirt from the 25-gallon tank using a clean cloth. Most importantly, remove any fish food leftovers to prevent them from decomposing inside the tank.
30-gallon tank
A 30-gallon tank is a medium-sized tank for aquarium hobbyists. Substrate decorations take up a lot of space inside the tank. Therefore, you need to keep in mind the space for the substrates as well as the guppies. A 30-gallon tank can accommodate 15 guppies or fewer. The remaining space is enough for your guppies to breed and dwell.
A 30-gallon tank is also large enough for breeding guppies. You can start with two males and four females in the tank and let them breed to fill up the aquarium. Because guppies give birth every month, your aquarium will be full in two to three months, and there will be no more space for breeding.
You can sell or give out the excess guppies when the aquarium is full. To keep them, buy another tank and separate the males to one tank and the females to the other tank.
A 30-gallon tank is much heavier with many guppies, and it needs proper care to keep the fish healthy. Change 30% to 40% of the water every week and clean the tank. Always remember to remove the fish food leftovers when cleaning the tank to avoid toxin accumulation.
40-gallon tank
A 40-gallon tank is much heavier than all the tanks I have talked about above. It also carries so many fish. You have to place the tank strategically so that it will not be moved frequently from one place to another. Keep 20 guppies or fewer inside a 40-gallon tank.
Use a 40-gallon tank to breed guppies or decorate your home and office spaces. As the population of the guppies increases, you can transfer some to another tank. Unlike the smaller tanks, a 40-gallon tank can accommodate more than one aquarium plant.
The fish and fry will also have plenty of hiding and eating grounds. However, a 40-gallon tank is much heavier and more delicate. Promote oxygen circulation using an aquarium filter and change 30% of the water twice a month. Ensure the resulting water parameters are similar to the original water to avoid stressing the guppies.
55-gallon tank
A 55-gallon tank is huge, and it gives the guppies plenty of space to thrive. You can use the tank to breed guppies and add multiple aquarium plants and substrates of your choice. Keep 27 guppies in a 55-gallon tank and decorate the aquarium according to your taste.
Some of the best aquarium plants for a 55-gallon tank include Java moss, Java fern, and Moneywort. Because the tank is so big, put it in a location with less traffic and far from direct sunlight.
Direct sunlight heats water and lowers oxygen concentration. Even worse, sunlight promotes the rapid growth of algae in an aquarium, causing breathing difficulties to guppies. Change 30% of a 55-gallon tank twice a month. That will give guppies a clean and healthy environment to thrive. I also recommend an aquarium filter for such a tank.
65-gallon tank
A 65-gallon tank is heavy and fragile. Like a 55-gallon tank, it requires a strategic location where you will not move it often. A 65-gallon tankcan accommodate 32 guppies if you don’t add many decorations. If you decorate it heavily, keep fewer than 32 guppies in the tank.
The tank is spacious enough for breeding guppy fish. Additionally, you can keep other fish species alongside guppies if you have a 65-gallon tank. Before putting fish of different species together, make sure they cannot prey on each other, and that both fish share the same water conditions.
Because of its size and weight, cleaning and maintaining a 65-gallon tank can be challenging. Generally, change 25% of the water every week and clean any dirt and food debris accumulated in the tank.
75-gallon tank
A 75-gallon tank is big enough to hold up to 34 guppies without decorations inside the tank. Try keeping guppies with their compatible tankmates, such as platy and mollies, in a 75-gallon tank.
Both the tank and the fish require great care and maintenance. A 75-gallon tank also requires fixed structural support to be stable. On the other hand, the guppies will need more food and more hiding grounds.
Clean and prune the aquarium plants and substrates every month. Also, change 25% of the water every month without removing the fish. Having an aquarium filter is an added advantage.
Minimum tank size for guppies
The minimum tank size for guppies is a 5-gallon tank. The tank is small and easy to clean and maintain. It can only accommodate three guppies; either three males or three females. It is also more portable than tanks bigger than 50 gallons. You can use a 5-gallon tank to decorate small spaces in your living room and office.
Signs your aquarium is overcrowded with guppy fish
Happy guppies are always swimming and playing through their hiding places inside the tank. If you notice less activity in your guppies, your aquarium is probably overcrowded.
Here are some signs that your aquarium is overcrowded with guppy fish.
Your guppies are dying
Waking up to a dead guppy in your aquarium can be a sign that your aquarium is overcrowded. Fish grow and thrive when there is plenty of space and correct water parameters.
If you notice your aquarium fish dying without a particular reason, you want to start by fixing the tank size and making sure your stocking is done correctly. Other than that, you want to make sure oxygen and other supplies are enough for your fish to prevent them from dying overnight.
Guppies are gasping at the top of the tank
When an aquarium is overcrowded with guppies, the oxygen supply in the tank goes down, and the level of toxins increases. These will make the fish gasp at the top of the tank to reach for oxygen.
In fact, if you notice your guppies swimming at the top of the tank most of the time, they are likely overstocked. Find the right tank size for guppies to keep them happy, which is likely increasing the tank’s capacity or reducing the number of fish in your current tank.
Increased ammonia level in the tank
Guppy waste and food leftovers contaminate aquarium water. When you measure ammonia levels in your aquarium, and it is more than zero, that is a sign of an overcrowded tank. The guppies might die within a few hours. Promote oxygen circulation using an aquarium filter and change 30% of the water twice a month.
Suggested For You:
Do Guppies Eat Algae? (What Type)
Can Guppies Live With Dwarf Puffer Fish?
Are Guppies Aggressive Fish? Do They Fight?
Angelfish and Guppies – Can They Live Together?
References
Baldonado, E. (2016). Guppy Care Sheet. AquariumKids
IFGA. (2017). Basic Care. International Fancy Guppy Association.
Leave a Reply