Crayfish can be amazing pets. However, keeping them in the tank may also become monotonous for some aquarists, and thus they start looking for suitable tank mates for their crayfish.
Generally, it is not recommended to keep crayfish in a community tank with fish, freshwater snails, frogs, shrimp, turtles, crabs, etc. They are best kept in a species-only tank. However, there can still be some exceptions to the rule.
The main problem is that crayfish are omnivorous and opportunistic feeders, their behavior is also specific and complex. Therefore, finding appropriate tank mates for these crustaceans is probably one of the most challenging aspects of this hobby.
So, can crayfish co-exist peacefully with other tank mates? In this article, I decided to summarize my thought regarding this question.
Crayfish and Their Instincts
I need to start off by saying that it is important to understand crayfish’s instincts. It can help us choose optimal tank mates to suit better their inborn, habitual behavior.
All crayfish species are opportunistic feeders. They are highly adaptive and will try to snack on whatever is available in the tank, and… there is nothing wrong with that! It is just the survival instinct asserting itself. That is what crayfish are programmed to do.
In addition, most crayfish species, despite their size, are quite aggressive and territorial in nature. Territorial conflicts often turn violent if somebody comes too close to them because crayfish are solitary animals and mostly interact even with each other only during mating.
| Therefore, while some crayfish species might be small and cute, they are still actually a pretty big threat in a community tank setting. Crayfish have a good reaction and also have a tendency to react defensively. |
As we can see, even though it can also vary by the individual, but you just need to understand that crayfish are aggressive in general. For example, even when crayfish are threatened by a bigger fish, instead of escaping, they may not hesitate to take chunks of fins. I assure you, their pincers can do some very serious damage!
List of Popular Aquarium Crayfish and Tankmate Compatibility
| Species (size) |
Temperament | Fish | Shrimp | Snails | Frogs | Other crayfish species |
| Cambarellus diminutus up to 1 inch (2.5 cm) |
Conditionally peaceful |
Possible | Possible | Yes | No | No |
| Brazos Dwarf Crayfish up to 1.5 inches (3 cm) |
Conditionally peaceful |
Possible | Possible | Yes | No | No |
| Dwarf Mexican crayfish up to 2 inches (5 cm) |
Conditionally peaceful |
Possible | Possible | Yes | No | No |
| Cambarellus shufeldtii up to 1.5 inches (3 cm) |
Conditionally peaceful |
Possible | Possible | Yes | No | No |
| Cambarellus pure up to 1.5 inches (3 cm) |
Conditionally peaceful |
Possible | Possible | Yes | No | No |
| Cambarellus texanus up to 1.5 inches (3 cm) |
Conditionally peaceful |
Possible | Possible | Yes | No | No |
| Cherax destructor up to 8 inches (20 cm) |
Aggressive | Possible | Possible | No | No | No |
| Procambarus milleri up to 4 inches (10 cm) |
Semi-aggressive | Possible | Yes | No | No | No |
| Signal Crayfish up 4 inches (10 cm) |
Aggressive | No | Possible | No | No | No |
| Orange crayfish up 4 inches (10 cm) |
Semi-aggressive | No | Yes | No | No | No |
| Marbled crayfish up to 5 inches (12 cm) |
Semi-aggressive | No | No | No | No | No |
| Procarambus Clarkii up to 5 inches (12 cm) |
Aggressive | No | No | No | No | No |
| Blue crayfish up to 5 inches (12 cm) |
Aggressive | No | No | No | No | No |
| Cherax pulcher up to 5 inches (12 cm) |
Aggressive | No | No | No | No | No |
| Cuban crayfish up to 3 inches (7 cm) |
Aggressive | No | Possible | No | No | No |
| Rusty crayfish up to 5 inches (12 cm) |
Aggressive | No | No | No | No | No |
| Cherax Boesemani up to 6 inches (15 cm) |
Aggressive | No | Possible | No | No | No |
| Red claw crayfish up to 13 inches (35 cm) |
Semi-aggressive | No | Possible | No | No | No |
*Yes – Generally compatible (low risk of aggression)
*No – Not advised (very high risk of aggression)
*Possible – Caution advised (medium risk of aggression, the result also depends on the individual)
Crayfish and Potential Aggression
Of course, we can find on the Internet lots of stories of having crayfish and other tank mates that peacefully coexist in community tanks. In my opinion, this is the main reason why there are so many aquarists who consider the idea of making a crayfish community tank.
| You need to take all these stories with a grain of salt. If it works for them it does not mean that it will work for you, and, of course, do your own research! |
Even dwarf crayfish of the genus Cambarellus are still not completely peaceful and inoffensive.
Sure, in most cases, they will not significantly limit your options as their bigger cousins do but their behavior can be different from one another. Just like in the human world, you can have a ‘crazy’ crayfish that will be more aggressive than they are supposed to be.
Important: You need to know that fish, frogs, shrimp, snails, etc are able to sense predators. Therefore, even if crayfish will not catch them, it will definitely stress them anyway. Even short-term stress may have adverse effects on their health. If it continues over time it may weaken their immune system, and shorten their lifespan, making them more vulnerable to diseases.
Crayfish and Their Instinct of Opportunistic Feeders
Crayfish are very opportunistic feeders and scavengers, eating anything from algae, detritus, animals, and plants, either living or decomposing.
Their diet is characterized by a wide diversity of food items. In captivity, they will eat almost anything that is available in the tank.
From a crayfish perspective, you are either predator or prey in the wild. So, if you hope that you can change this attitude by giving crayfish more food, you are wrong.
Sure, well-fed crayfish will be less aggressive but you cannot completely change this behavior because it is something that they will do instinctively. Therefore, do not be surprised when your crayfish will still try to catch any potential prey when given a chance.
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Crayfish in Community Tank. Tips
If I did not convince you to keep crayfish in the species-only tank and you are still willing to take risks, there are a few precautions that you might want to take.
| Important: Keep in mind that following these rules cannot guarantee any result and you will have to intervene if necessary. |
1. Fish:
DO NOT keep crayfish with bottom-dwelling, slow-moving, or fish with long fins (like Betta). They will be the first ones to get hurt.
You need to give your fish at least a chance to survive. Pick only fast-swimming, top, and/or mid-dwelling fish. For example such as
- Zebrafish,
- Harlequin Rasbora,
- Boraras,
- Neon Tetras,
- Clown Killifish,
- Least Killifish,
- Guppies,
- Endlers,
- Dwarf swordtails,
- Mollies, etc.
2. Hiding Areas:
Make sure that you have lots of hiding places in your tank. Crayfish also require shelter and protection to minimize their stress (stressed crayfish may behave aggressively). This is especially crucial for the molting process when crayfish are soft, weak, and relatively immobile.
In addition, shrimp and fish will also need hiding places to avoid or reduce potential contact with crayfish.
You can use all types of leaves, rocks, driftwood, PVC pipes, plastic mesh, artificial plants, live plants, and other decorations to enrich the environment in your tank.
Tips:
- Crayfish do not swim. Therefore, floating plants and/or plants with large and thick leaves will be ideal hiding and resting spots, especially during nighttime when crayfish are active and fish are sleeping.
- Many crayfish species will eat, cut, and uproot plants in the tank. Ideally, you will need fast-growing, hardy, and cheap plants that you are ready to lose.
- Break a line of sight by using large objects (such as stones, driftwood, etc.) everywhere in the tank. Crayfish are less aggressive when they do not see the target. So, it will be safer for other tank mates.
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3. Tank size:
The tank size also matters a lot if you want to keep any tank mate with crayfish. It is way easier to hunt in small tanks.
A large aquarium will let everybody have more space to roam around and avoid crayfish. So, the bigger the tank the better!
4. Feeding:
Do not let them starve! It will definitely affect their behavior in a negative way by making crayfish more aggressive.
Tip: Crayfish are nocturnal animals. To avoid food competition and potential fights, it is better to feed them at night (at least in the evening). Therefore, by doing so, you will replicate the conditions and environment under which they eat naturally.
5. Conspecific:
Crayfish are natural loners. So, it can be really hard to put several crayfish together. They are not social and do not like to be kept in groups. In fact, most crayfish species will guarantee to fight fellow members of their own or other species.
According to multiple studies, cannibalism is one of the main causes of low survival in many crayfish species. Males, in particular, are extremely likely to fight and eventually kill one another when housed together.
Multiple crayfish should be kept only in groups of one male with multiple females but two adult males would need far more space to prevent territorial fighting.
Note: Dwarf crayfish are generally gregarious and less aggressive, amenable to stocking at relatively high densities. Nonetheless, it does not mean that they are social. It simply means that they can just tolerate high stocking densities better than other crayfish species.
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6. Avoid:
- Large and/or aggressive, and/or boisterous fish (such as Cichlids, Goldfish, Arowana, Monos & Scats, Jack Dempsey, Oscars, etc.).
- Turtles (many turtles eat shrimp, crabs, and crayfish ).
- Most types of freshwater crabs (because of their aggressive nature).
- Frogs (crayfish can easily damage their skin and eventually kill them).
What if I introduce crayfish gradually into the community tank?
Some people think that if you introduce crayfish last, they may get used to their new tank mates from the beginning. Unfortunately, it will not work. This trick often works with fish but not with crayfish.
The main problem is that crayfish are not smart crustaceans and, generally, operate on their instinctual nature. They do not have long-term memory to learn.
Therefore, there is no need to establish their potential tank mates first, then add crayfish.
Do Your Research Beforehand!Before getting crayfish, you have to understand their requirements and the potential consequences. Impulse purchases often have a very bad effect. People do not understand that their nature limits options if they want to keep them in a community tank. |
In Conclusion
Keeping crayfish in a community tank together with fish, shrimp, snails, frogs, etc. requires some careful consideration. In crayfish, aggression varies across species.
I strongly believe that large crayfish species generally do not have suitable tank mates. Therefore, it will not be the best course of action.
It can be a little bit easier with dwarf crayfish species. However, it is still absolutely not possible to predict the outcome because it is going to depend on the individual.