What Fish Not to Put with Guppies?

As peaceful and friendly fish, guppies will get along with a variety of tank mates. However, the situation might depend not on guppies but on their tank mates.

Some fish species are simply incompatible with guppies, either due to their size, territorial behavior, carnivorous preferences, or simply their overall personalities. In those cases, guppies are always on the losing end since they are typically sociable and easy-going fish that don’t do well with stress.

Your job is to provide your guppies with a safe and peaceful living environment, which means you should avoid pairing them with incompatible tank mates. Today, we will discuss about the most notorious fish species to avoid when looking for compatible tank mates for your guppies.

10 Tank Mates to Avoid Housing with Guppies

We will discuss the 10 most well-known creatures that don’t get along with guppies, but the list is way longer than this. This makes for a good start anyway, helping you avoid fish species that could hurt or even kill your guppies. These include:

1. African Cichlids

Several aspects are making African Cichlids a poor choice for your guppy tank. The first one is their behavior. African Cichlids are inherently more aggressive than many other fish species, particularly guppies. They are territorial and require a lot of water volume to thrive.

Your typical Cichlid will reach around 3-4 inches in length, with some species reaching 8 inches in size. You will need a 55-gallon tank to accommodate 1 8-inch-long Cichlid. The 3-inch Cichlid alone requires at least 30 gallons of water.

Unless you’re getting a 100-gallon tank, there’s no way you can pair African Cichlids with guppies.

Other than that, African Cichlids are omnivorous and enjoy similar environmental conditions to guppies. Not that it matters anyway.

2. Barbs

Barbs are schooling fish that require a lot of water volume to thrive. Even the smallest of the species, with specimens growing up to 2.5 inches, still need at least 20 gallons of water. You can probably pair guppies with this Barb strain (Black Ruby Barb), especially since they share many of the guppies’ preferred environmental conditions.

The problem is that Barbs are extremely active and interactive fish that love to interact with other fish around them. This behavior is counterproductive against guppies that prefer calmer tank companions. Barbs’ excessive personality may stress out guppies and force them into hiding.

When it comes to larger Barbs, the incompatibilities between the 2 species are even more visible. Some Barb species can grow up to 3-4 times the size of a male guppy, which can place guppies into the ‘prey’ category.

3. Goldfish

There are numerous problems with Goldfish that make them unfit tank mates for a variety of fish species, including guppies.

The main problem is that Goldfish grow to enormous sizes compared to guppies. The smallest goldfish strain will measure around 4-5 inches, which is already double the size of an adult female guppy. The largest specimens can reach in excess of 15 inches.

They require a lot of water volume, which is already a problem in and of itself. Other than that, Goldfish are an aggressive species that don’t enjoy teamwork. They also carry deadly parasites and diseases that could quickly wipe out your guppy population.

These fish are definitely some of the worst contenders on this list.

4. Male Betta Fish

The male Betta fish has reached this list purely based on its innate aggressive behavior. Betta females are rather friendly and docile, enjoying the company of other fish, including guppies. All problems start coming with the males, who tend to be more territorial and aggressive.

It’s also worth mentioning that Bettas are smart and require constant mental stimulation, otherwise they might get bored or depressed. They will invent activities, such as chasing guppies around the tank and nipping at their fins when that happens.

Knowing how sensitive guppies are when bullied, the problem becomes obvious.

5. Angelfish

Angelfish are omnivores, generally peaceful, and enjoy water requirements similar to guppies. But this is where the compatibilities between the 2 species end. Angelfish are also larger than guppies, as they can grow up to 6 inches and won’t shy away from attacking smaller fish for food. They can also become aggressive at times, seeing as they are Cichlids after all.

Then there’s the fact that one Angelfish requires at least 20 gallons of water, and you can see why they aren’t really compatible to guppies.

6. Killifish

So many aspects make this fish species incompatible with guppies that I don’t even know where to start. Let’s enumerate some of the core differences between the 2:

  • Diet – Killifish are carnivores. This alone should discourage you from pairing them with guppies, especially since Killifish can grow to 3.5 inches, double your average male guppy.
  • Water requirements – Killifish require colder waters to thrive and remain healthy. Their preferred water temperatures revolve around 62 to 74 F, whereas guppies require 72 – 82 F. There is no way you can pair the 2 without making heavy compromises one way or the other, with grim consequences.
  • Tank requirements – One pair of Killifish requires at least 20 gallons of water. This means there’s no place for guppies in a Killifish tank.
  • Overall species compatibility – Killifish are incompatible with many fish species, not just guppies.

7. Pictus Catfish

First, the good aspects. The Pictus Catfish is a friendly and peaceful species that prefers to live in the cover of caves and plants. They tend to roam around the tank’s substrate in search for food, whether it’s algae, plants, or small animals. By ‘small animals’ we also mean guppies, since the Pictus Catfish can grow to 5 inches, triple the size of a guppy male.

The necessary minimum tank size is 50 gallons for one fish. This alone is a deal-breaker if the Catfish’s taste for guppies didn’t dissuade you first.

8. Oscar Fish

Oscars are incompatible with most smaller fish species, which also include guppies. Most Oscars will reach sizes of up to 9-12 inches, with a maximum size of 16 inches. They are giants that require at least 50 gallons of water to thrive.

Larger fish may even require a 75-gallon tank which is already way more than you might have had in mind for your guppies. Oscars also grow extremely fast at around 1 inch per month during their first year.

The optimal water temperature is around 76-78 °F. Anything lower than that will make them vulnerable to diseases, which is incompatible with guppies, whose ideal temperature can go down to 72 °F.

9. Dwarf Pufferfish

The Dwarf Pufferfish can grow up to 1.4 inches, typical of a guppy male. This sounds small enough not to pose a threat to guppies, right? Yes, but no. The Dwarf Pufferfish is a small, cute, cuddly, and aggressive carnivore with a bad attitude and a scary appetite.

This tiny fella is the smallest of its species but compensates via its rugged personality and aggressive demeanor. Despite its small size, the fish requires at least 5 gallons of water due to its exaggerated territorial behavior, making it incompatible with many fish species.

The Dwarf Pufferfish doesn’t shy away from attacking larger fish, hurt them, and even eating them after they’re dead. This rings disaster for your guppies, who are peaceful by nature and won’t pose much threat to the Pufferfish.

10. Turtles

Turtles are the worst tank companions you can choose for your guppies. Or for any fish species, for that matter. Turtles are omnivores, require large tanks, and like to live alone, if possible. They will eat any fish crossing their territory, so long as it’s small enough for them to kill them. And it most likely is, especially since aquarium turtles can reach 10-12 inches in size or more.

And if you think turtles are too slow to catch the fish, consider 2 crucial aspects:

  • Turtles are very fast and nibble swimmers, capable of impressive agility underwater
  • Time is on their side since the fish have nowhere to go

Many aquarium keepers complain about their turtles eating their Goldfish, which are significantly larger than guppies. What do you think will happen to your guppies?

Some aquarium keepers have suggested that guppies can survive if there are enough plants and hiding spots in the tank. But what life will those guppies have, constantly hiding and dodging that massive predator lurking in their tank?


Rather than testing your luck with more unorthodox options, I suggest pairing guppies with compatible fish species. Keep your guppies safe and inform yourself of each new species you aim to add to your tank.

I also suggest monitoring the aquarium for several days after introducing the new inhabitants to make sure everyone gets along.

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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