Why Is My Crayfish Not Moving?

If you are keeping crayfish for some time now, you might have experienced your crayfish not moving. Though ‘crayfish not moving’ is not very common, it can happen and you need to know why it is happening. Here’s everything I know about this issue:

Crayfishes stop moving or move very little during the molting process. They can also stop moving due to excessive stress, wrong water parameters, or unsuitable tank mates.

Though crayfishes generally stop moving during the molting process, many other reasons can be responsible for this type of behavior. Let’s discuss them in details.

3 Most Probable Reasons Behind Crayfish Not Moving

It is very hard to exactly pinpoint the reason for your crayfish not moving. Many things can trigger this type of behavior in your crayfish. Here’s what I think the most common 3 reasons are:

blue crayfish roaming inside tank
Owner: Cassica Milleville

1. The Crayfish Is Going Through Molting

This is the most common and most probable reason. When crayfishes go through molting, they get very vulnerable. At this time, other tank mates can attack them.

So, to keep themselves safe, the crayfishes lie still in a corner or inside the hiding place. You may find them moving very little, not interested to foods, etc. There is no need to worry and it is a natural defense mechanism of the crayfishes.

Generally crayfishes can take several hours to a day for the whole molting process. So, you might see your crayfish not moving for up to a day or two.

If it is longer than that, then some other thing is causing this type of behavior and you need to investigate.

2. The Crayfish Is Stressed

The crayfish might stop moving if it is stressed for some reason. Stress can happen for many reasons. Here are some of the most common ones:

Wrong Water Parameters

Every aquatic animal needs ideal water parameter ranges to live happily. When you ensure the idea water parameter ranges, you’ll replicate the ideal home for that animal. If the water parameters do not fall within that range or change drastically, it can seriously stress out the animal.

Here are the ideal water parameter ranges for crayfish:

Water ParameterIdeal Range
Ammonia, Nitrite, NitrateClose to 0 ppm
Temperature65 to 80 Degrees Fahrenheit (19 to 27 degrees Celcius)
pH6.5 to 7.5
GH4-10 ppm
KH3-10 ppm
TDS100-300 ppm
Important NoteConsistent water parameters are more important than trying to hit the correct number. If your tank water pH is 8.0, it’s not the end of the world for crayfish. Just make sure the parameters are consistent and do not change rapidly.

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Crayfishes are generally very hardy creatures. Even if your pH, KH, GH do not fall in the ideal range, it won’t be very fatal. Just try to keep the parameters consistent.

However, if there is ammonia or nitrite in the water, it can be very lethal for the crayfish. So, if the crayfish is not moving, check the water parameters. If you see any sign of ammonia, do a water change immediately and try to find out the source of the ammonia.

Generally overfeeding, dead organic matters, etc. give rise to ammonia spike. So, look for these carefully.

If you want to know more about water parameters for crayfish and how to check these, then I’ve written a detailed guide for you. You’ll know everything about water parameters for crayfish in that guide. Check it out!

orange crayfish creeping out from cave hideout
Owner: Jon Shockey

Newly Bought

Your crayfishes can also show signs of stress if they are just bought from the fish store. This is normal and the stress should go away with a few days.

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However, ensure that your tank has the proper setup for crayfish along with plenty of hiding places and substrate to dig. If you don’t know what substrate to choose so that the crayfish can dig, don’t worry.

I’ve written a detailed guide on that as well. Check out my substrate guide for crayfish to know what substrate to choose and how much should you use.

No Hiding Places

Crayfishes need hiding places. It is a must for them. In wild, crayfishes dig through the substrate or hide under rocks to save themselves from potential danger.

You’ll also need to replicate the wild environment for them. If there is no hiding places, the crayfish can easily get stressed out and cease to move.

Fortunately, providing hiding places is extremely easy & cheap. The easiest option is to cut some PVC pipes and throw them in the tank. The crayfish will use the PVC pipes as its hideout comfortably.

If you want something more naturally aesthetic, you can glue rocks together to form cave like shape. They look more natural and pleasing to the eyes.

There are also many hiding decorations you can buy from the fish store. Whatever you choose, make sure there is enough hiding places in the tank for your crayfish.

Unsuitable Tank Mates

If there are other predator fishes or creatures in the aquarium, they can stress out your crayfish. If the tank mates are not suitable, your crayfish might even get eaten.

So if your crayfish is stressed, check if the tank mates are suitable for crayfish or not.

Here are examples of some bad tank mate choices:

  • Cichlids: Cichlids are a very bad choice for crayfish tank. They are extremely aggressive and can eat your crayfish.
  • Other Crayfish: Generally crayfishes are very territorial themselves and can’t handle another one of their own in the same tank. So if you keep multiple crayfishes in a small tank, it is inevitable that they’ll fight to death and cause stress to each other. It is never recommended to keep multiple crayfishes in an under sized tank.
  • Monster Fishes: Other monster fishes like Arowana, Oscar, Giant Gourami, etc. are not suitable tank mates for crayfish. I don’t think I need to explain why they are unsuitable.

3. Crayfishes Are Nocturnal

Crayfishes get more active during the night and hide during the day. So, if your crayfish is not moving, check it again at the night. Chances are it will move to another place or look for food in the tank.

orange crayfish on plant leave
Owner: Laura Trimblett

What Can You Do If Crayfish Doesn’t Move?

We’ve already talked about the most common reasons for your crayfish not moving. Now, let’s discuss what to do in such a situation:

Just Leave The Crayfish For 24-48 Hours

Crayfish generally takes several hours to a day for molting. It is a very long and tiresome process for the crayfish. During molting, it doesn’t move or go after foods.

So, if your crayfish is not moving, give it about 24-48 hours and check again. Your crayfish should complete the molting process by then and start moving again!

Check If You Are Looking At The Old Exoskeleton Of Crayfish

As I’ve said, crayfish generally shows this type of behavior during molting. If your crayfish hasn’t moved even after a day or two, look closely. You might be looking at the old exoskeleton of the crayfish.

The exoskeleton of crayfish looks exactly like the crayfish. I have seen many crayfish keepers mistaking the exoskeleton as their crayfish and freaking out!

Just get a tweezer and gently touch the ‘thing’. You’ll understand if it is the exoskeleton or real crayfish!

Do A Water Change Of The Crayfish Tank

if the crayfish is not moving due to bad water quality, a large water change will help a lot. Just do a 50% water change and check the water parameters. See if everything is in the right range.

If you see any of the parameters sticking out oddly, then you’ll know what’s causing the issue. Suppose if you’ve found out there is ammonia in the water.

So, you need to deal with this ammonia. Generally large water changes daily can help you out with it. Also, look for the reason what’s causing this ammonia spike in the tank. When you find out the source, try to get rid of it.

That’s how we should solve any issue with the tank water.

blue crayfish peeking through an aquarium decor hideout
Owner: Mary Kot

Do Crayfish Play Dead?

Generally, crayfish tend to show territorial behavior towards their tank mates. Due to their aggressive temperament, it’s pretty unusual to think of them playing dead.

But, crayfish can play dead. You shouldn’t get panicked by finding your crayfish motionless while these crustaceans may be just making you fool by playing dead.

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On several crustacean forums, a few crayfish owners shared their experience of finding their crayfish playing dead. These crustaceans may show immobile behavior due to stress, improper water parameters, predatory attacks, etc.

If you notice your crayfish to lay on one side and motionless, your crayfish may be sleeping. The researchers found the slow electrical activity of crayfish brains during such postures. Your crayfish will stink, in case it becomes dead.

Gently Poke

If the crayfish doesn’t move even after a couple of days, gently poke it with something. See if there is any sign of movement.

If there isn’t any, then the crayfish is likely dead and you need to take it out before it gets rotten.

I am sorry. The hobby can get cruel sometimes! Just try to figure out what you did wrong, learn from your mistakes and next time prepare your tank better for the crayfish!

Is My Crayfish Dead Or Molting?

When you notice your crayfish floating, you may assume it is dead first. But, a floating crayfish need not always be dead.

Molting is a vulnerable process for crayfish. It can take around a few hours to several days for crayfish. During this process, the crayfish are not able to do any movement. That’s why you might notice crayfish float during the molting process.

On the other hand, it’s pretty normal to find dead crayfish to float. Initially, a crayfish will sink when it’s dead. After a while, the dead crayfish will start floating.

However, a molting crayfish is responsive towards the touch and another sensory. If you put a light on a molting crayfish, it’ll show a response. Moreover, a crayfish will move if it is alive.

On the contrary, a dead crayfish doesn’t show any signs of movement in sensory stimuli. In addition, you can look for bad smells. A dead crayfish will stink. But, a molting crayfish will not have any bad smell.

crayfish grazing on a leaf
Owner: Vanessa Brilli

Why Does The Crayfish Hide After It Molts?

The hard exoskeleton of crayfish works as a shell of protection for these crustaceans. It’s too obvious for crayfish to hide when they do not have this safeguard.

In the process of molting, crayfish shed their old exoskeleton since these crustaceans do not fit in their old shell. As a part of their growth, crayfish require a new exoskeleton in their body. No wonder it’s a complex and vulnerable procedure for crayfish to shed their hard exoskeleton.

The exoskeleton plays a significant role to protect the soft body of crayfish from the environment. In addition, the exoskeleton is a water-tight barrier for crayfish. This outer shell supports crayfish and functions as a sensory interface.

So, crayfish become too stressed and weak without the protection of their outer shell. You can take a look at this article to know how crayfish protect themselves.

After molting, crayfish turn into easy prey for their predators. Since crayfish do not have any protective barrier over their soft body, they tend to hide during post molting period.

If the predators of crayfish find them without an exoskeleton, they can readily nibble or hurt the soft flesh of crayfish. That’s why crayfish remains too stressed after molting.

You’ll notice crayfish hide until their new shell gets hardened. Otherwise, your crayfish may get eaten by their predators.

If you want to know details of the molting process, you can go through this article.

Why Is My Crayfish On Back Not Moving?

You must be aware that crayfish are highly territorial and active creatures. So, it’s an unusual behavior of crayfish to stay on the back without any movement. There are several reasons behind this.

Let’s check out the probable causes of such behavior.

1. Your Crayfish Is New

If your crayfish is new to the tank, it may take some time to adapt to the new environment. In the beginning, your crayfish may remain stressed. As a result, new crayfish may lie on its back.

In addition, it may not show any sign of movement. You can gently poke your crayfish to see if it’s alive. When your new crayfish become familiar with the new tank, it’ll be active again.

white crayfish beside a skull decor
Owner: Sandy Sharp

2. Nocturnal Trait

Sometimes, there’s nothing to worry about when your crayfish do such unusual behavior at night. Since crayfish are nocturnal, these crustaceans do not move at night time by laying on their back. Count it as a nocturnal trait of your crayfish.

3. Your Crayfish Is Stressed

Another reason why your crayfish is on its back, not moving, is stress. There can be several stress factors for crayfish.

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Such as aggressive tank mates, poor water quality, improper water temperature, insufficient hideouts, ammonia spikes, etc.

4. Your Crayfish Is Molting

If your crayfish lays on its back without moving, it may be molting. Generally, crayfish remains too stressed during their molting stage. That’s why the crayfish stop their usual activity and movement. In the molting process, it’s a common behavior for crayfish to flip over.

Sometimes, crayfish become upside down in the pre-molting stage. When your crayfish finish the molting stage, they’ll start moving again.

Where Do Crayfish Hide?

In the wild, crayfish tend to hide behind vegetation in the shallow part of the water. Sometimes, you may find them within creeks or under rocks.

The place of hideouts depends on the setup of your crayfish tank. If the crayfish tank is well planted, your crayfish may hide behind the leaves of plants.

Besides, your crayfish may hide if you keep hideouts in the tank. These crustaceans seek security in hiding spaces. So, the crayfish tend to hide in all kinds of corners where they can fit themselves.

Crayfish can hide behind rocks, logs, pieces of PVC pipes, clay caves, or other décor items. Moreover, these crayfish hide under the substrate. They can burrow themselves under gravel like the way crayfish hide under mud.

What Does A Dead Crayfish Look Like?

A dead crayfish looks dull and sluggish. Your crayfish will not move if it is dead. A dead crayfish will not show a response to any sensory stimuli like an active crayfish.

Besides, a dead crayfish will lose its color gradually. But, it always does not happen. So, your dead crayfish may appear dull to you.

Moreover, your dead crayfish may lay upside down. Sometimes, a dead crayfish stays on its side with its claws and legs.

In the first few hours of death, a dead crayfish will sink at the tank bottom. When the internal organs of crayfish start decomposing, the dead crayfish may float up to the tank surface. Click here to know the probable reasons why your crayfish is floating.

Finally, you should look for the sign of smell in a dead crayfish. When a crayfish dies, it’ll stink badly.

blue crayfish coming out of a skull eye
Owner: Sandy Sharp

Frequently Asked Questions

Why is my crayfish upside down?

There are several reasons why a crayfish may be upside down. It could be a sign of molting, which is a normal process in which crayfish shed their exoskeleton to grow.

It could also be a sign of illness, such as a bacterial infection or a parasite. Stress or fatigue from overcrowding, lack of oxygen, or poor water quality could also cause a crayfish to be upside down.

Why is my crayfish not eating?

There are several reasons why a crayfish may stop eating. One common reason is that it is about to molt, which is a natural process in which crayfish shed their exoskeleton to grow.

Another reason could be that the crayfish is sick or stressed due to poor water quality, overcrowding, or lack of oxygen.

In some cases, a crayfish may not be eating because it is not being offered the right type of food.

It is important to ensure that the water is clean and balanced and to offer a variety of foods, such as plant-based diets and algae wafers, to encourage feeding. 

How do crayfish move?

Crayfish move in several ways, including creeping forward, walking sideways, and even swimming. They move forward by creeping, which involves using their legs to push themselves along the bottom of their environment.

They can also walk sideways, which is useful for navigating tight spaces. When swimming, crayfish beat pairs of paddles called swimmerets on each body segment in sequence, starting at the back of the animal and moving forward.

The movements of each segment keep a precise difference in timing, while varying in speed and force.

How to tell if a crayfish is stressed?

Crayfish can exhibit several signs of stress, including reduced activity levels, loss of appetite, and hiding. They may also show signs of aggression or become more territorial.

In addition, stressed crayfish may exhibit physical symptoms such as discoloration, frayed or damaged appendages, or abnormal behavior such as flipping over or swimming erratically.

Why is my crayfish tail curled?

A curled tail in crayfish can be a sign of stress or aggression. When a crayfish is feeling threatened or stressed, it may curl its tail under its abdomen as a defensive posture.

This can be triggered by changes in the environment, such as a move to a new tank or the presence of other fish.

Another possible reason for a curled tail in female crayfish is that they are carrying eggs underneath their tail.

Why is my crayfish laying on his side?

A crayfish laying on its side could be a sign of illness, stress, or molting. If the crayfish is sick, it could be suffering from a bacterial infection or a parasite.

Stress from overcrowding, poor water quality, or lack of oxygen could also cause a crayfish to lay on its side.

Molting is a natural process in which crayfish shed their exoskeleton to grow, and they may be inactive for a period of time before and after molting.

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Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of AcuarioPets.com. I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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