Guppies are small fish, meaning that they do not need large tanks to live a happy and healthy life, but they also do need a sensibly sized tank, especially if you are planning on keeping them in large schools.
Not only this, but guppies prefer large areas to swim around freely and explore, they can become stressed out if they don't have much space and feel crowded.
However, a large tank for your guppies can be problematic too. This is why tank size and stable water parameters are imperative in ensuring that your guppies are healthy.
This guide will run you through the best tank size for guppies, the number of guppies for certain tank sizes, and which tanks you should avoid using for your guppy fish.
Ideal Guppy Tank Size
Before we continue, if you would like to watch my video covering this topic, feel free to do so below:
Ideally, if you are keeping a large school of guppies and you have the right budget, space, and time to maintain your aquarium, a 40 gallon (151.4 liters) tank is the perfect guppy tank size.
A large tank like this will alleviate any overpopulation issues and constant water changes due to the waste production in a small tank.
Larger water area in aquariums is more stable and therefore not prone to ammonia spikes, unlike in small aquariums.
Additionally, the more space you have to work with, the more lively and awesome you can make your aquarium with live plants and decorations, which is great as plants are great natural water filters!
However, due to the sheer volume of water in large aquariums, you will need to acquire suitable equipment to handle the large volume of water. Heaters for your guppies, as well as filters, and air pumps are all harder to maintain in a large aquarium.
If you can manage a 40 gallon tank you should certainly use one for your guppies. Due to the size, you can keep many guppies, and even breed your guppies without the fear of overcrowding.
Below is a graphical summary of a 40 gallon guppy tank, including the dimensions, empty weight, and full weight:
You can also add different species of freshwater fish to create a community tank environment.
Guppies are incredibly social, and should never be kept alone, which is why they need to be kept in schools of their own kind and also thrive in big community tanks with compatible freshwater fish.
Due to their peaceful nature, guppies can live with a whole host of different freshwater fish - make sure you check out our guppy tank mates guide for some inspiration!
Minimum Tank Size for Guppies
The minimum tank size for keeping guppies is 10 gallons (37.85 liters), you should try and avoid keeping guppies in tanks under 10 gallons.
Depending on your experience level, you should keep between 5 and 7 guppies in your 10 gallon tank, certainly no more than 7!
Once the tank equipment has been completely set up, the 10 gallons will not be able to hold 10 gallons of water, which is important to note, and why we encourage the usage of a larger aquarium.
We also understand that it is not realistic for people to buy, manage, and maintain a 40 gallon tank, so a great compromise would be a midsize tank that is 20 gallons (75.7 liters).
Funnily enough, many people ask whether or not you can keep a singular guppy in a one gallon fish tank.
When we looked at this question - it was rather amusing at first, and we weren't even sure whether or not you could feasibly acquire a 1-gallon fish tank. Well, you can, and technically, you could keep a guppy in one.
However, just because a guppy can live in a 1 gallon tank - it certainly doesn't mean it is a good idea, and in fact, you should NOT do it, under any circumstance, as guppies are schooling fish and incredibly social.
Likewise, it is not a good idea to keep a guppy in a glass bowl and we have written a detailed article on why it is not good for them.
How Many Guppies Can You Keep in a Fish Tank - Final Thoughts
So, should you could keep between 5 and 7 guppies, you would need a 10 gallon fish tank.
Equally, you can keep between 12 and 13 guppies in a 20 gallon tank - most guppy species are typically 1.5 inches (3.8 cm) in length, which is pretty small.
For a 40 gallon tank, you could conceivably house about 20 guppies. However, we recommend between 15 to 18 guppies.
Also, you'll need to take into consideration any other tank mates you would like them to live with since that will reduce the number of guppies you can have in a certain sized tank.
However, if you are just starting out in the hobby, we recommend keeping fewer guppies as it is less responsibility, allowing you to learn and grow as a fish keeper free of too much stress.
Larger tanks with less fish in them will likely keep your fish healthier and happy too, less susceptible to stress and disease.
You should also maintain a ratio of 1 male per 3 to 4 female guppies to reduce male fighting and an abundance of guppy fry!
Guppies should live in groups of three minimum in order to live comfortably, however, if you did keep only 2 guppies, your minimum tank size would need to be 5 gallons.
5 gallons (18.9 liters) would be the more preferred size if you wanted to have 3 instead of 2 guppies.