How Many Guppies In A 10 Gallon Tank? Tank Conditions & More

    Do guppies need a filter

    How Many Guppies In A 10 Gallon Tank?

    If you are staring with your first tank, you will probably want to keep guppies. They are excellent fish to begin with. Add the fact most aquarists start with 10-gallon tanks and we get an obvious question: how many guppies in a 10-gallon tank should you keep?

    Brief Overview Of Guppies

    Guppies come in many beautiful and colorful varieties

    Guppies belong to the Poeciliidae family. Their size ranges between 0.6 – 2.4 inches, and you can keep between 5 and 10 individuals in a tank of this size. Guppies come in all colors possible, and they are peaceful fish that are extremely easy to keep. Their lifespan is up to 2 years.

    Calculating How Many Guppies Are Suitable For a Tank

    In order to get accurate information on how many guppies in a 10-gallon tank you should keep, there is a simple rule to follow. The rule is simply known as 1 gallon of water for 1 inch of fish. Keep in mind that there is no 10 gallons of water inside a tank with a 10-gallon capacity. There are also gravel, filter, heater, and many other components that will need space as well. In other words, in a 10-gallon tank, you will have 7 or 8 gallons of water.

    If you take an average size, which is 1.5 inches, and divide the tank capacity with this value (10/1.5=6.6), you will get the most accurate answer. In this case scenario, we can see that up to 7 guppies should be placed in a tank. This is actually the ideal amount, especially if you are a beginner. If you are an expert, you can keep 10 or even more. We used the size of 1.5 inches as an example. Try to figure out the average size of your guppies in your own tank.

    There is one additional thing to consider. Male guppies are always smaller than female ones. This means that you can accommodate 10 of them in a 10-gallon tank without an issue. But, a female guppy is 2 inches in size. If you plan to keep only females, you will need to limit their number to 5 per 10 gallons of water.

    Of course, most aquarists will want to keep both male and female guppies. The ideal ratio is 1:2 (male:female). By using the ratio, you can have the best results, and your tank won’t be overcrowded. In other words, a 10-gallon tank can accommodate 4 males and only 2 female guppies.

    The 1-inch per gallon rule is great for small fish like guppies. But it works less well when you start getting into bigger fish. One 10-inch oscar cichlid does not equal ten 1-inch guppies in terms of overall bioload. So save this rule for fish that are, at most, 3 inches long

    What if the Guppies start Breeding?

    Female Guppies

    If you decide that you will keep male and female guppies in your tank, you can deduce that they will breed. They will breed almost to extreme levels, and you will have baby guppies on a regular basis. They are definitely interesting fish when it comes to breeding. First of all, they will reach maturity within 5-6 months of their life.

    As you may know already, there are visual differences between males and females.

    • Males are smaller, have a narrower anal fin (gonopodium), and they are brighter in color.
    • Females have a dark spot behind their gonopodium, and it will get even darker when they are pregnant.

    Males are able to tell when females are pregnant, so they don’t lose time. They will make a short contact with females and pass their spermatophores (sperm basically). From that sperm, the female guppy can become pregnant multiple times. Females will grow the young inside the egg, which is inside the body. That’s why guppies are known as ovoviviparous.

    The eggs will transform into embryos within 5 days. After 21-30 days (gestation process), she will give birth. But, she will give birth again within one month or usually less. It is important to add that you must remove the fish 7 days before the end to a breeding tank or simply remove them after the birth so they won’t eat the fry.

    We had to explain this process so you can understand how fast guppies will breed. If you keep males and females in the same tank, the answer to how many guppies in a 10-gallon tank question will almost be irrelevant. Within a month, you will have too many of them. There are a few alternatives. You can donate the young, you can keep them in a separate tank, or you can sell them.

    If you decide to sell them, place them in a separate tank to maintain the ideal count in the primary aquarium. Guppies are very common and popular fish, meaning you will have a lot of success selling them. If you want to donate them, most pet stores with aquariums do accept these.

    Guppy Tank Setup and Tank Conditions

    Guppies live in freshwater. They are native to South America, so they need warm water and conditions to mimic the natural habitat. Ideally, the water temperature should be between 75 and 82 degrees Fahrenheit. You should place a heater on one side and a thermostat on the other side of your tank. By using this trick, you can measure the water temperature accurately.

    Although we gave you an answer to how many guppies in a 10-gallon tank, you can keep guppies in tanks of other sizes as well. Remember that the smallest size is 5 gallons. There is no limit to the upper size.

    Make sure to maintain a steady pH value. The ideal pH value is from 7.0 and up to 7.2. Yes, they can tolerate various values ranging between 5.5 up to 8. But they like the specified value the most.

    Guppies also prefer low to moderate hardness (dissolved minerals) in their water. Fortunately, tap water in most countries has some mineralization in it. Many fish are stressed by this, including tetras and other soft water fish. But guppies prefer tap water with minimal treatment besides dechlorination!

    You need a water filter as well. The model and the type you can get will depend on the tank and the size you are using. Most users pick a small filter that will hang on the back of a tank. This is the ideal setup for 10-gallon tanks. But if you have a 50-gallon tank, you will need an external filter with a canister.

    In general, guppies do not require some advanced and special, expensive setup. They can live and enjoy a very affordable tank setup.

    For non-breeding guppy tanks, you will need to add live plants (such as Hornwort), substrate, and rocks to the tank. Guppies will spend most of their time at the top of the middle section of a tank, but they occasionally swim around at the bottom section as well. 

    Those who will want to breed guppies need a bit different setup. The tank’s bottom should be bare (no substrate, rocks, etc.), and you need plants that float so young fish can hide. The ideal plant for this case scenario is Java Moss.

    Guppy Tank Maintenance

    Maintaining the tank where guppies live is simple. You need to invest in a high-quality water filter that will do most of the work for you. But, you also need to replace water on a regular basis. If you have an overstocked tank with as many guppies as possible, you will want to change between 30% and 50% of water per week. If you keep fewer guppies in a tank, you can change less water.

    One thing to remember is that you must not wash the water filter with regular tap water. It contains chlorine that can kill beneficial bacteria. Avoid keeping biological media for a long period of time because it can also kill off beneficial or good bacteria inside a tank.

    Believe it or not, there are no other maintenance steps to worry about. Guppies are extremely easy and simple to keep, and they are great for beginners. If you keep other fish in the same tank, you may want to pay more attention to the maintenance.

    Guppy Tank Mates You Can Consider

    Guppies agree best with other guppies. In other words, the best mate is additional guppies! Of course, this is an obvious fact, and you may want to know about other fish species that can be kept in the same tank alongside guppies

    Fish that should be considered must be peaceful as well. In a nutshell, most, if not all livebearers, can be added as mates. Those who want to keep guppies with non-fish species should consider African Dwarf Frogs and Red Cherry Shrimp. Due to these two non-fish species’ peaceful nature, there won’t be anything to worry about. Here are a few examples of ideal mates for guppies:

    Keep in mind that some fish must be avoided in this case scenario. Almost all large and aggressive fish should be avoided, or your guppies will be eaten! Fish that absolutely you must avoid from keeping in the same tank with guppies are Barbs and Cichlids. Don’t forget that aggressive tetras should also be avoided.

    Conclusion – How Many Guppies Can I Keep In A 10 Gallon Tank?

    So, how many guppies in a 10-gallon tank should you keep? The ideal number is under 10. Try to remember that their gender and size will determine the actual number. If you keep male and females, keep them in a 1:2 ratio. Females are always bigger than males, so they must be kept in a smaller number.

    Other than that, there are no complicated facts to know or complicated maintenance steps. Guppies are extremely easy to keep and breed. We hope that you have found this guide useful!


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