Natural Selection in Guppies

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In this article I cover an interesting topic regarding the guppy fish species: we’ll see how they behave in the wild and how can they adapt so well in their environment.

Since guppies are so popular among both beginner and veteran fish keepers, it’s helpful to know how they behave in their natural environment. This way, if you buy some of these fish, you’ll know better how to set up a great habitat for them to live in.

First of all, let’s see what the natural habitat of this breed really is. This way, you’ll get a better overall picture about their life in the wild.

Natural Habitat of Guppies

Usually, guppies will live in clear tropical water of the Caribbean islands, like Trinidad and Tobago. Also, it’s found in South America, in countries like Guyana, Brazil and Venezuela.

These are the places where they appear naturally, however, people have introduced them to every continent except Antarctica.

They like to live in small ponds or slowly moving waters. You won’t find guppies in fast flowing rivers or other places with powerful water currents. However, a river can serve as their home, if it’s moving very slowly, or if it has sections where the water stays in place.

What about the water composition? Guppies like more saline waters than usual. Most other tropical fish will live in fresh water environments, but guppies will do well in both salt and fresh water habitats. They like to swim in salty waters, but not as salty as marine water (sea water).

Because they are tropical fish, guppies live in warm waters. In most cases, you’ll find them in habitats that contain water at about 72 to 79 degrees Fahrenheit.

The pH level of the water they live in, tends to be between 5 and 9. However, to be sure they live a healthy life in your tank, keep these numbers between 6.5 and 8.

To find out more about the pH level for guppy tanks, I recommend that you read my article regarding this topic, entitled “Best pH Level for Guppies“.

There, you’ll find out much more about this topic, like how to increase or decrease pH levels in a fish tank, and what is the best pH level for guppies in general.

Now that you know how their natural habitat feels like, let’s see if they have any natural predators that threaten them in the wild.

Guppy Predators in the Wild

Since guppies are not big fish by nature, they have many natural predators. Some of these are the following:

  • Cichlids – all sorts of them
  • Killifish
  • Birds – all sorts of birds that live besides water

Of course, there are other predators for guppies as well, but these are the most notable ones that eat them regularly. Basically, any carnivorous fish that is larger than a mature guppy, will most likely hunt for guppies in the wild.

To not get eaten by these predators, guppies tend to school together, to protect themselves. This is not true in every situation though. They only do this, in places where predators move in large numbers, or where predators visit very often.

Now that you know about their natural predators, we should talk about their diet in the wild:

Guppy Diet in the Wild

Guppies that live in the wild, will eat all sorts of things to stay alive. Some of the most common items are the following ones:

  • Diatoms
  • Invertebrates
  • Algal remains
  • Plant fragments
  • Mineral particles
  • Aquatic insect larvae

Even so their diet is this varied, most guppies will eat algae in the biggest proportion. This is why many fish keepers will buy guppies for their aquariums. They are great at cleaning your fish tank from algae remains, and other small waste particles.

There are exceptions from this though. Guppies that live in different areas of the globe, might have other things in their diet as the main element. For instance, guppies that live in Trinidad, are known to eat mainly invertebrates instead of algae remains.

Guppies’ diet is also corelated to the abundance of any particular food. What does this mean more exactly?

In places where algae remains are more abundant than invertebrates, guppies are more likely to live on algae remains. It’s quite logical actually. But just like before, this isn’t a rule that always applies.

In other cases, guppies might consume more invertebrates, even if they find these harder. Why is that? Because invertebrates are much more nutritious than algae, and guppies will go for what is better for their health, like any other animal for that matter.

Actually, guppies that live mostly on invertebrates, will have a better diet than those that eat mainly algae remains.

Their diet can also be related to the presence of competitors. In what way? If there are other fish species in the area that also eat algae (for example), guppies might start to live on something else, invertebrates maybe.

This way, their diet will vary from other guppies that might live only 10 miles away, but without any competitors.

How Natural Selection Influence Evolution?

How do guppies evolve over time considering what I mentioned up until this point? Of course, they won’t present huge changes. However, guppies that eat differently or live in different environments, might look a little different from their other “brothers”.

For instance, their environment will influence their behavior and look quite a bit. If the habitat presents many dangers from predators, guppies can start to adopt interesting colors, that resemble their habitat. This way, they can hide themselves easier from predators.

Guppies that don’t reach a healthy state when mature, will most likely die or get eaten by predators.

This way, only the strong and healthy specimens will stay alive in their natural environment. But maybe you’re asking yourself how can guppies adapt so well, like mentioned above? Let’s see!

How Can Guppies Adapt So Well?

Usually, guppies are quite good at adapting to their environment, as seen from the example mentioned above. What is the reason behind this?

Like any other animal, guppies will adapt to their habitat, because they have to survive there. Studies have shown that guppies that were moved from one place to another different habitat, adapted their behavior to survive.

For instance, guppies that were moved to areas where less predators lived, started to give birth to larger and fewer fry, thus maintaining their numbers like this. Basically, in places with less predators, less fry are enough to keep the species alive.

On the other hand, such an adaptation was not noticed with guppies that colonized a high-predation environment. The opposite happened, they started to give birth to more fry, in the hope of staying alive as a species in that new habitat.


As you can see from above, guppies are an interesting fish breed, that will adapt to their environment quickly and efficiently.

Also, we’ve seen what their natural habitat is like, so if you plan on buying some for your home aquarium, you’ll know better how to set it up for them.

Updated: April 7, 2022

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