Can You Keep One Guppy Fish Alone?

Most fish are social creatures, and this goes for guppies as well. You can’t keep one specimen alone for too long before behavioral problems begin to appear.

Guppies need social reinforcement to regulate their behavior, and they enjoy other guppies’ companies. It keeps them healthy, active and regulates their hormonal functioning.

Not to mention, the entire concept of keeping one guppy alone is rather peculiar. You set up an entire tank just to have one guppy swimming around. It would’ve made sense if the guppy were a larger, sedentary fish, but guppies aren’t like that.

They are generally small and colorful fish that thrive in moderate communities where they can interact with other fish.

Not to mention, keeping one guppy alone will make for quite a depressing sight.

Why Most People Think About Keeping One Guppy Alone

Most guppy owners think about keeping only one guppy either due to the tank’s size or lack of experience. A 10-gallon tank, however, should suffice for a guppy population of 5 to 8. There’s no reason to get an aquarium that’s smaller than that.

There’s also the concern that guppy populations come with drama and fish interactions that beginners don’t know how to interpret or manage. This isn’t a real problem either, since guppies are extremely easy to maintain.

The important thing to note is that male guppies can become territorial and confrontational during mating. This is why you shouldn’t keep more than 1 or 2 male guppies in the same tank, depending on the tank’s size. A guppy society will also self-regulate with minimal intervention from your part.

There’s no reason to keep one fish alone. If you have the tank setup ready, consider abiding by the golden ratio of one male to 2 or 3 females. A 10-gallon tank should hold 2 such groups.

When it comes to setting up the ideal aquarium with stable fish dynamics, here are the best options available:

Mixing One Guppy With Other Fish

If you’ve decided to have no more than one guppy, you can, at least, add other fish to the aquarium. This, however, will come with several challenges, including:

  • Overcrowding – Not all aquarium fish are of the same size, and some require more space than others. If you plan on mixing species, I recommend learning how much space each fish needs. Otherwise, you can easily overcrowd the aquarium, which can lead to poor water oxygenation and a crowded and stressful environment.
  • Aggression concern – You should always handpick the fish species you plan to mix because they are not all compatible with one another. Guppies, for instance, are friendly and calm in general, but other species might not be. But other species like the Piranha, arowana, the Oscar fish, or the Tiger Barb are not. Placing these aggressive species with in the same aquarium with guppies can spell disaster fast.
  • Overbreeding – Some fish breed more effectively than others. Having multiple species in the same tank will raise problems like overbreeding, where tracking pregnant females can be tricky.
  • Balancing the water parameters – This is probably the most important point to note. Not all fish require the same environmental parameters. Some fish enjoy more tropical waters like guppies, while others thrive in colder environments. You should understand each species’ water requirements before placing them together in the same environment.
  • Feeding issues – Some fish will eat more than others, and some will be more aggressive during feeding. If bigger fish species don’t eat enough, they might attack smaller individuals, including guppies.

Keeping multiple fish species in the same tank is entirely possible if you’ve already solved this problem. But if you’re already willing to do that, you might as well have multiple guppies. They are easy to maintain and are generally peaceful and sociable creatures.

Have a Female-Only Tank

This is the safest solution for people who don’t want the headaches of mixed species of male-only tanks. Females are more obedient and peaceful by nature since they don’t display territorial or aggressive behavior.

However, remember that females can keep the males’ sperm inside their bodies for up to 10 months after mating. If the females have mated before removing the males, expect many pregnancies over the months to come.

If not, then you shouldn’t worry about the aquarium filling with guppy fry anytime soon.

The main downside of having a female-only guppy tank is the lack of diversity. Female guppies are duller in coloring compared to the males. If that doesn’t bother you, you’re fine. If it does, but you don’t want to add male guppies to the female population, resort to species mixing.

Introduce new, peaceful tank mates that will add color and diversity to the tank. If you want to do that, see the previous point about mixing different fish species and take all the necessary precautions.

Have a Male-Only Tank

Male guppies are more colorful, providing the tank with a different energy than what females could bring. The main problem to mention here is the testosterone.

Male guppies are naturally more aggressive, intrusive, and territorial and display bullying behavior towards weaker males. This can lead to fin injuries, and even death as the males will nibble on each other’s fins, causing infections in the process.

To minimize these risks, have a larger tank with only several males, which will reduce the frequency of the encounters.

Keep a Mixed Guppy Tank

If you consider the possibility of having either a female or a male-only tank, you might as well go for a mixed bag. There’s no real reason to keep one guppy alone, and gender-specific tanks don’t perform so well in terms of fish dynamics.

Males, for instance, will display more vibrant colors when near females and will also be less aggressive overall. Especially if there are multiple females around (2-3 females for one male should suffice).

The key problem to note here is the risk of pregnancy. If you don’t want your guppies to breed, you need to control the population. I would say you have two options available in this sense:

  1. Let nature follow its course – Don’t intervene if you see a pregnant female guppy. The gestation period is about 21-30 days, after which the female will give birth to 20 to 50 guppy fry. In some cases, they might deliver 100 or even close to 200 fry. That’s plenty of small guppies swimming around, providing adult guppies with a lot of food. Guppies show cannibalistic tendencies and will almost always mistake their fry for live food. The adult population will consume the fry after birth, only leaving a few, which you can remove later on after the dust has settled.
  2. Quarantine the female – It’s quite easy to spot a pregnant female. Some of the most relevant indicators include the inflated belly, the pregnancy spot in the lower abdomen, and the hiding behavior when labor approaches. You should relocate the female to a different tank with the first signs of labor and move it back after it gave birth. You can then do whatever you desire with the resulting fry, including feeding them to your guppies, killing them, or even grow them for profit.

Once you’ve figured out how to control your guppy population, everything else will come naturally. While it may sound counter-intuitive, it’s actually easier to care for multiple guppies than one alone. That’s because the guppy population will self-regulate. So long as you maintain the water within the ideal parameters, prevent overcrowding, and deal with the breeding, everything else is easy.


I would advise against keeping a guppy fish alone. It will affect its health in the long run, and the aquarium will look depressing, just like the guppy’s state of mind.

Go for a mixed population instead, controlling the number of males and avoiding overcrowding. You can even throw other species into the mix, so long as they are peaceful and can coexist with guppies. These include swordtails, honey gouramis, cory catfish, platies, and many others.

I hope this article managed to show that growing guppies in a small, controlled population is preferable to keeping single guppies.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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