Guppies might not be the fish that first comes to mind when you’re picking stock for an aquaponics setup, but they’re a genuinely solid choice. Beyond being easy on the eyes, a guppy population can actually help your whole system run better, and they’re known for being tough, resilient little fish. Before you add any to your tank, though, it pays to understand what guppies need and how much variation they can handle, since getting the conditions right from the start gives your system its best shot at thriving. Keep in mind guppies do take a bit more care than some other beginner fish, so it’s worth reading up before you dive in. Here’s what to know.

Guppy varieties

More than 40 recognized guppy varieties exist. Rather than cover them all, here are the two you’re most likely to encounter:

Common guppy

Sometimes called the million fish or rainbow fish, this is the guppy you’ll find almost anywhere in the world, and it’s a go-to for both home aquariums and aquaponic setups. Males show off bold coloring while females tend to look plainer.

Endler guppy

A close relative of the common guppy, the Endler stands out with striking red, green, and silver coloring and a calm, easygoing temperament. One thing worth noting: Endlers prefer warmer water, while common guppies do better in cooler water with a steady current. Females also grow a bit larger, reaching about 1.4 inches compared to males, which top out around 1 inch. Decades of selective breeding for color have produced an enormous range of patterns, hues, and body shapes — domestic guppies are typically flashier and bulkier than their wild ancestors.

Ideal temperature for guppies

Guppies do best between 72°F and 78°F, though they can handle brief swings outside that window without thriving as well. pH is more forgiving — anywhere from 6.7 to 8.5 works, which is a wide enough range to make day-to-day management fairly easy.

How fast do guppies grow?

Like most fish, final size depends heavily on how much room they have. As a general guide, males land between 0.6 and 1.4 inches, while females run larger, from about 1.2 to 2.4 inches.

Can guppies share a tank with other fish?

Mixing species in an aquaponics system isn’t common, since you’re juggling multiple sets of needs at once. Guppies, however, get along fine with calm, non-aggressive tankmates such as white cloud mountain minnows, neon tetras, or certain catfish — none of which will stress your guppies or lead to interbreeding.

Guppy questions, answered

What do guppies eat?

Guppies do well in a tank with plenty of plant life, and floating plants in particular tend to make them feel more secure. Dry fish flakes make a good staple diet since you can easily see how much they’re eating and adjust portions. Live food like bloodworms or Cyclops works too, but watch portion sizes carefully — guppies will overeat and become obese if given the chance.

How large do guppies get?

These are genuinely small fish. If you’re planning a guppy-based aquaponics system, think carefully about your available space, since that determines how many fish you can responsibly keep. Males typically max out around 1.4 inches and females around 2.4 inches — neither is a large fish.

Are guppies edible?

Technically, yes. But because they’re so small, you generally can’t gut or clean them before cooking, which creates two issues: first, improperly cooked guppies carry a higher risk of bacterial illness, and second, their tiny size means you’d need an enormous number of them to make an actual meal. Even though they breed fast, they’re not a practical food source for you or your household — most people who keep guppies simply don’t eat them, even though it’s technically an option.

What’s the lifespan of a guppy?

Guppies reproduce quickly, partly because their lifespans are short and partly because their small size makes them easy targets for predators. In the wild, a guppy typically lives around two years, but inside a well-run aquaponics system they can live as long as five years.

Where can you buy guppies?

Nearly any local pet store carries guppies — they’re common, inexpensive, and easy to find, which should make sourcing them a low-stress part of setting up your system.

Will tilapia eat guppies?

Generally, this combination isn’t advisable. While tilapia are still small, they may be smaller than your guppies and coexist without trouble. But once tilapia outgrow the guppies, they’re likely to start eating them, which obviously isn’t good news for your guppy population.

Are guppies lively fish to watch?

The main job of fish in an aquaponics system is producing waste that becomes nitrates for your plants, but it’s still nice to have fish that are fun to watch. Guppies tend to swim near the surface and move quickly, making them engaging, active fish to observe. For anyone with a bit of aquaponics experience already, a guppy system is a solid choice.