Can Blue Crayfish and Guppies Coexist Peacefully in a Pet Aquarium? Find Out Here!

Blue crayfish and guppies living together in a pet aquarium present potential challenges, primarily due to the predatory behavior of the crayfish and the increased stress on the guppies. 

It’s best to keep your crayfish and your guppies separated in different tanks.

However, by putting in place proper environmental precautions, monitoring stress levels, and providing adequate living space, it is possible to maintain a relatively harmonious aquarium.

Understanding Blue Crayfish and Guppies

Guppy Overview

Guppies (Poecilia reticulata) are small, colorful, and lively fish that make an excellent choice for a community aquarium. They come in various colors and patterns due to selective breeding.

Guppies are peaceful and get along with other non-aggressive fish species.

These fish are also very adaptable and can thrive in various water conditions, with a preferred water temperature range between 75-82°F (24-28°C) and a pH of 7-8.

Guppies are omnivorous, feeding on a diet consisting of flakes, live, and frozen food, as well as some vegetables.

However, it is crucial to consider their small size and the potential danger larger or more aggressive species pose to them in a shared aquarium.

Considering both species’ characteristics, it is essential to evaluate whether blue crayfish and guppies can live together harmoniously in an aquarium without any conflicts.

by Lauren Deneweth (CC BY-SA 4.0)

Blue Crayfish Overview

Blue crayfish, also known as Procambarus alleni, are a popular freshwater crustacean species. They are known for their striking blue color and can grow up to 6-8 inches in length.

Blue crayfish appreciate an aquarium with hiding spots, ample space to move, and a clean environment.

Regarding their diet, they are primarily omnivores and opportunistic feeders. This means they consume various food sources, including plants, fish, and other small aquatic creatures.

Their relatively aggressive behavior and predatory nature can pose a risk for some tank mates.

by Bleckdraco (CC BY-SA 4.0)

Potential Challenges and Solutions

Crayfish Predatory Behavior

Blue crayfish are known to be aggressive and are likely to hunt and eat guppies. To minimize this risk, consider creating a complex environment within the tank, filled with hiding spots and multiple layers of vegetation.

This will make it more difficult for crayfish to catch the guppies, allowing them to coexist in the same space with less risk.

Additionally, feeding the blue crayfish a balanced and satisfying diet can help reduce their hunting behavior. By providing them with high-quality pellets that cater to their dietary needs, along with occasional treats like frozen bloodworms, you can help ensure they don’t feel the need to hunt the guppies.

Some hobbyists have used blue crayfish for fish population control.

How Do Crayfish Hunt?

Blue crayfish are opportunistic predators and scavengers.

Sensing Prey: Blue crayfish have well-developed sensory organs, including antennae and sensory hairs, which help them detect movement and chemical cues in the water. They rely on these senses to locate potential prey.

Ambush Hunting: Blue crayfish are ambush predators. They usually hide and wait for prey to come within their reach. They often take shelter in crevices, under rocks, or in burrows they dig themselves.

Crayfish hunt at night: They become more active and emerge from their hiding spots as darkness falls. Sleeping fish become easy targets.

Prey Selection: They will eat whatever they catch. Their diet typically consists of small invertebrates like insects, worms, snails, and small fish. They also scavenge on dead animals and plant material.

Hunting Technique: When a potential prey item comes within range, the crayfish will extend its front claws, known as chelae, and grab the prey. The chelae are strong and well-adapted for capturing and crushing prey. The crayfish may use its smaller appendages to manipulate and bring the captured prey to its mouth.

Blue crayfish are not highly mobile hunters. They rely more on ambush tactics and scavenging rather than actively chasing down prey. However, they sometimes use their tail to jump backward to attack.

Creating a Harmonious Environment

When setting up an aquarium to house blue crayfish and guppies, it’s essential to create a harmonious environment that allows cohabitation between the two species.

This section highlights factors such as aquarium size and setup, water parameters and maintenance, as well as hiding spots and decor.

Aquarium Size and Setup

An appropriate tank size is crucial for maintaining a balanced environment for both species. A minimum tank size of 20 to 30 gallons is recommended to accommodate an adult blue crayfish, while guppies require at least a 5-gallon tank. A larger aquarium allows for ample swimming and hiding spaces, reducing the likelihood of territorial disputes1.

To help create suitable territories for both species, consider selecting a substrate of medium-sized gravel. This allows crayfish to dig burrows and guppies to swim freely near the surface. Additionally, include ornamental plants and other decor pieces to provide additional cover.

Water Parameters and Maintenance

Maintaining favorable water parameters is vital for the health and well-being of both guppies and crayfish. Key water parameters to monitor include:

  • Temperature: Guppies thrive in water temperatures between 74-82°F, while blue crayfish prefer temperatures in the range of 65-75°F. Aim for a stable temperature around 75°F to accommodate both species.
  • pH: A pH level of 7.0 to 8.0 is ideal for ensuring the safe coexistence of crayfish and guppies2.
  • Ammonia, nitrite, and nitrate: Both species are sensitive to excess waste buildup. Regularly checking and maintaining close-to-zero levels of ammonia and nitrite, and a nitrate concentration below 20 ppm is essential.

Water changes of about 20-25% on a weekly basis can help maintain stable water parameters in the tank, ensuring a healthy environment for both species.

by A Captain D (CC BY-SA 3.0)

Hiding Spots and Decor

Providing a variety of hiding spots and decor is important for reducing stress and improving the quality of life for both guppies and crayfish. Consider incorporating the following elements into the tank setup:

  • Caves and shelters: Utilize commercially available decor elements or create your own crayfish shelters using PVC pipes, terra cotta pots, or rocks. These retreats allow crayfish to hide and molt in peace, reducing the risk of conflict with their tankmates.
  • Floating plants: Incorporate floating plants such as duckweed, water lettuce, or hornwort to provide additional cover for guppies to hide and rest.
  • Vertical elements: Include tall ornamental pieces and plants to create separate vertical spaces. This allows guppies to occupy the upper levels of the tank and crayfish to claim territory at the bottom, facilitating a more harmonious environment.

Monitoring Stress Levels

Stress is another significant concern for guppies and crayfish living together in a pet aquarium. The presence of an aggressive predator like the blue crayfish can increase stress levels in guppies, making them more susceptible to illness. Regularly monitoring the aquarium environment can help reduce stress for both species, which in turn can help create a harmonious environment.

  • Water quality: Check the water quality frequently, ensuring that there is adequate filtration and proper ammonia, nitrite, and nitrate levels. Poor water quality can lead to increased stress and may even contribute to aggression between the species.
  • No overcrowding: Providing a spacious and adequately-sized aquarium is crucial for minimizing stress. For blue crayfish, a tank size of at least 20 gallons is recommended. Guppies prefer a swimming space of at least 2 gallons per adult fish.
  • Barriers and shelter: Creating separate spaces within the aquarium for both species can help alleviate stress. Introducing visual barriers, like strategically placed rocks and decorations, can create smaller territories for each species.
by Carnat Joel (CC BY 2.0)


Blue crayfish are known to be territorial and can sometimes consume smaller, slow-moving fish. Guppies, being small and relatively fast swimmers, might be a gamble when housed with blue crayfish.

If you like this article you might also enjoy our article on Blue crayfish with snails.

About the author

Hi, I am Alex.
My passion is aquariums. I am especially drawn to betta fish. I love experimenting, learning, researching, and writing about them.

You can find the articles I wrote here

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