Why do Guppies Bite You?

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If you’ve own guppies, you may have noticed that they tend to bite your fingers or hand if you place it in their water. Guppies don’t have teeth, so they can’t really inflict any damage to humans, but their behavior seems peculiar nonetheless. They don’t mistake you for food, and they can’t eat you, so why do they do it?

Guppies display a variety of behaviors relating to mating, eating, bullying, social interaction. Today, we will discuss their preference for biting and bumping into your hands and fingers – a behavior that many aquarium fish will display.

Why Guppies Nibble on Your Fingers?

There are several reasons for that, including:

  • They recognize you – Guppies are smarter than most people give them credit for. They can recognize their owners, even though they have limited capabilities of showing it. They may see you sticking your hand in their aquarium as an opportunity to greet and interact with you. So, take this as a sign of affection if they do that.
  • Food potential – If you’re used to feeding your guppies directly from your hand, that may influence the fish’s behavior over time. Your guppies will eventually learn to associate your hand with food, so they will gather around it each time you immerse it in the water. The nibbling is their way of asking for food, which they know is coming.
  • Some more food potential – Guppies will eat you provided they have the opportunity. Quite literally. More specifically, they will nibble on the dead skin hanging from your hand that you may not even notice. Guppies will, however, given their feeding behavior and being used to spot tiny food particles floating in their environment.
  • Even more unexpected food potential – If you have a hairy hand, that’s even more incentive for guppies to bite on it. Your hairs will mimic the plants and fibers decorating their natural habitat, which guppies will investigate to look for food. It’s, therefore, expected for guppies to swarm around your hands, hoping to find something to eat.

On a different note, it’s generally a good sign if guppies come to nibble on your hands. That means that they feel safe and comfortable in their environment, safe enough to inspect your hand up-close and personal, knowing there’s nothing to be afraid of.

Why do Guppies Bite Each Other?

Guppies tend to nibble on each other’s fins and tails occasionally, despite not showcasing malicious intent. But sometimes, they do. Knowing the reason why your guppies seem to stalk or attack one another is crucial for differentiating between harmless and harmful behaviors.

Here are several reasons why guppies tend to bite each other:

  • Playful behavior – Guppies like to play at times, displaying specific behavior, which involves swimming frantically around the tank, hiding, and even nipping at each other. They won’t harm one another in the process, except maybe by accident. This is a normal social behavior, showing that your guppies are healthy and comfortable and feel safe in their environment.
  • Bullying – Bullying can occur between males as well as females. Each social group displays a specific pecking order that is kept by violence. It’s not uncommon to witness male and female guppies nipping and bullying lower-ranked individuals during meal time or even randomly. This behavior is also normal so long as it doesn’t go out-of-line and doesn’t degenerate into constant bullying and aggression.
  • Mating – The mating phase is an opportunity for a lot of harassment and violence, coming from both males and females. Males tend to be extra pushy and attempt to mate with females who have already mated and are no longer interested. As a result, females will use violence to discourage males from pursuing them anymore; which rarely works.
  • Overcrowding – Keeping too many guppies into a too tight space is bound to have undesirable outcomes. One of them is increased fish stress and aggression. Consider a larger tank if you have too many guppies in a tank and you see them fighting each other constantly.
  • Male-only tanks – Male-only tanks inevitably come with an extra flavor of violence thanks to the excess testosterone. Male guppies are naturally more territorial and will fight other males if they’re too crowded. The same occurs if there are females in the environment, just not enough. To avoid this situation, provide guppies with a plant-rich environment and plenty of hiding places, and keep a healthy male-to-female ratio. 2-3 females should suffice for each male.
  • Cannibalism – Guppies don’t usually cannibalize each other unless we’re talking about mixing adults and fry. Generally speaking, guppies don’t exhibit any maternal or paternal instincts, and they have no moral system preventing them from eating their own. Adult guppies will see their fry as prey and will eat them if given the opportunity.

If you notice your guppies displaying signs of aggression, assess the situation and take appropriate measures. In most cases, you don’t need to intervene, but ignoring those when you do may place your guppies at risk of injury and even death.

Can You Touch Your Guppies?

Yes, but I wouldn’t advise it doing it too often. You should also definitely hold them or get them out of the water. It won’t hurt the guppy immediately, but it will stress it out, which can affect its health over time.

In general, guppies and aquarium fish aren’t exactly the most caressing-friendly pets. If you want to interact with them, tap their aquarium glass or stick a finger inside the water so they can investigate it.

Should You Put Your Hand in Your Guppy Tank?

Placing your hand in your guppy’s water should hurt them, provided you don’t do it too often, and you take necessary precautions in the process. This includes rinsing your hands thoroughly if you’ve just washed them with soap or any other chemical that could hurt your guppies.

Guppies are rather sensitive to chemical changes in their water, and anything can throw them off. Other than that, doing it too often may also stress them out. Try to only interact with your guppies when absolutely necessary. Otherwise, let them do their thing and observe them from a distance.


Guppies use their mouths to investigate their environment, so it’s nothing weird about them nipping on your hands given the opportunity. Just make sure you don’t adopt the habit of placing your hand in their tank too often. And always rinse your hand thoroughly before doing so.

Updated: January 20, 2022
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