Why Did My Crayfish Die? 5 Most Common Reasons

Why Did My Crayfish Die

Crayfishes are generally very hardy creatures. If everything is right, they won’t die just out of the blue. So, if your crayfish has died, there is something wrong with your crayfish tank setup.

Crayfishes mainly die due to poor water parameters. They can also die because of larger & aggressive tank mates, uncycled tank, lack of oxygen and of course, too much age.

I have listed all the common reasons for crayfish death. Go through them one by one and check if you did anything wrong.

5 Common Reasons For Crayfish Death

1. Bad Water Parameters For Crayfish

Any aquatic animal needs their ideal water parameters for living happily. It is extremely important. We humans need clean & fresh air for a healthy and sound body. Same goes for any aquatic animal. They need their ideal environment to thrive.

If you are keeping crayfish in a hostile environment with bad parameters, it can soon die. So, you need to make sure the water parameters fall into the acceptable range for crayfish.

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.

As you can see, crayfish can’t handle even a little bit of Ammonia. Ammonia is detrimental for any aquatic animal. So, check for Ammonia in your crayfish tank water. Even if there is a little bit of Ammonia, it can cause the death of your crayfish.

All the other water parameters are important too but not as crucial as keeping 0 ppm ammonia. If you can’t hit the ideal range exactly, that’s okay. However, try to be consistent with the water parameters.

If your tank water pH is 7.2 today and 6.4 the next day, then this rapid fluctuation can cause stress to the crayfish.

So, consistency is the key when it comes to water parameters.

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Owner: Sandy Sharp

2. Crayfish Got Too Old / Unable To Handle The Molting Process

In a crayfish related facebook group, I have asked what are the most common reasons for crayfish death. Do you know what majority of the people answered?

Molting Failure!

Molting is a very delicate & sensitive process for crayfish. This can take even a whole day. During and after molting, a crayfish becomes very vulnerable. At this stage, other similar size fish or creatures can attack the crayfish.

Also, if the crayfish is old or stressed, then it might not recover from the stress of molting process. Molting requires a significant amount of energy. Unfortunately, most old crayfishes don’t have that type of strength left.

Another reason for molting failure can be improper diet. If the diet lacks nutrition like iodine, calcium, etc. then the crayfish can fail to molt. Iodine is extremely important for crayfish. It helps them to grow exoskeleton.

I know many crayfish owners who lost their crayfish due to bad diet. If you want to know what a proper crayfish diet looks like, read my guide on crayfish feeding.

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3. Uncycled Crayfish Tank

If you put your new crayfish into an uncycled tank, then most probably it will die within a week. Nitrogen cycle is one of the basics that you need to master for keeping aquatic animals. Without mastering this cycle, your aquatic pets will just keep dying.

I have written a detailed post on nitrogen cycle for shrimps. Though it is for shrimps, the basic concept is exactly same and you should read it before even buying the crayfish.

Let me share the basics briefly:

1st Stage: The Ammonia Rise

When we keep fish, crayfishes, etc. in a tank, they produce waste. There are also uneaten food particles in the tank. All these decaying organic matters produce Ammonia in the tank.

Ammonia is a chemical compound (NH3) that is very harmful for living creatures. A slight amount of it can cause the death of your pets. So, we need something to deal with this Ammonia.

That’s where beneficial bacterial colony comes in.

2nd Stage: Converting Ammonia Into Something Less Harmful

If your tank is properly cycled, then it will have a colony of beneficial bacteria in the filter media. The bacteria will use the Ammonia as a food source and convert it into Nitrite (NO2).

Nitrite is still very harmful for living creatures and need to be dealt with.

3rd Stage: Converting Nitrite Into Something Lesser Harmful

The bacterial colony will again use the Nitrite as food source and convert it into a chemical called Nitrate (NO3). Now, Nitrate is comparatively much less harmful than its predecessors. Even plants can absorb Nitrate as nutrient.

However, when too much Nitrate builds up, it can get harmful for the fish, crayfish, etc. That’s why we need to change the tank water regularly. By changing the tank water, we keep the Nitrate level in balance. So, it doesn’t harm our pets.

Owner: Vanessa Brilli

4. Unsuitable Tank Mates For Crayfish

Most of the time, you’ll hear hobbyists complaining about how their crayfish has killed other fishes. It is natural and will happen if you don’t maintain the compatibility.

Though crayfishes perform the role of hunter mostly, it can also be a prey to larger fishes and creatures. So, if you are keeping crayfish in a monster fish tank, then the other fish can certainly eat your crayfish. Unsuitable tank mates is another very common reason for losing your crayfish.

Here are the suitable tank mates for dwarf crayfish:

Good Tank MatesBad Tank Mates
TetrasBetta fish
Swordtails, Mollies, Platies, etc.Shrimp
Red Tail SharkCorydoras
Hatchet FishPlecostomus
Rosy Red Minnows, Rainbow Darters, etc.Any Bottom Dwellers
Barbs, Danios, etc.Other Crayfish
NB:Even the good tank mates can fall into the prey of crayfish. When it comes to crayfish, nothing is certain.

5. Lack Of Oxygen Can Drown Crayfish

Many people often wonder if crayfish can drown themselves. Though the question seems to be weird, but the answer is YES. Crayfishes can drown themselves.

Crayfishes need lot of oxygen in the water. In the wild they can get out of the water and comfortably live out of water for days. This is because crayfish has special gills that allows it to absorb oxygen from the air. However, for this to happen, the gills need to be moist. That’s why in a mushy & damp area, crayfishes can live out of water for days.

So, if your tank water doesn’t have enough oxygen in it, the crayfish will try to get out of the water. If it can’t, the inevitable result will be death.

Experienced crayfish keepers always recommend to keep an air pump ON in the crayfish tank 24/7. It will ensure enough oxygen in the water. You can also keep some large stones in such a way that their peaks breach the water level. That way, the crayfish can crawl out of the water whenever it needs.

What Are The Signs Of Crayfish Death?

These are some of the common signs of crayfish death that I can think of right now:

  • Your crayfish will seem very lethargic. It will stay in one place most of the time. Even at night, the crayfish will be uninterested to roam around the tank for food.
  • The crayfish will show no interest to foods.
  • It will move very slowly.
  • Sometimes after a bad molting, the crayfish might flip over.
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Owner: Sandy Sharp

Is My Crayfish Molting Or Dying?

Crayfish tend to remain immobile in several stressful situations, including molting. On the other hand, a dead crayfish will not show any response. Hence, people often get confused about whether their crayfish is molting or dying.

In the process of molting, a crayfish remove its old exoskeleton to develop a new exoskeleton. It’s a natural part of their growth.

Since crayfish shed their shell in molting, these crustaceans feel stressed throughout the molting period. It can take several hours to weeks. As a result, crayfish stop their activities during their molting period.

But, these crayfish can respond to stimuli even if they are molting. They show reaction and movement due to touch, poke, or light sensory.

On the contrary, you’ll not see any movement from a dead crayfish. Besides, it may start stinking.

Why My Crayfish Died After Molting?

Molting is a vulnerable and sensitive process for all crayfish. This process requires a lot of energy for crayfish to shed their old exoskeleton. Meanwhile, old or weak crayfish may not be able to complete their molting.

Due to lack of energy, many crayfish die after molting. You might even see your crayfish not being able to get out from the old shell. In such a case, your crayfish may die being stuck in the molting.

Do Crayfish Float When They Die?

The crayfish owners often get confused due to noticing their crayfish floating. These crayfish may float when they die. Since crayfish float in molting, it’s pretty hard to ensure your crayfish’s death.

You shouldn’t assume your crayfish is dead instantly when you see these crustaceans floating. Check out whether these crustaceans show any response to stimuli.

What Does A Dead Crayfish Look Like?

The very first sign of a dead crayfish is its unresponsiveness. A dead crayfish will not move from a specific place for a long time. It’ll not show any interest in food or prey since it is dead.

Besides, you’ll notice no movement of the gills and antennae of a dead crayfish. Your dead crayfish will become motionless. One sign that is unavoidable in a dead crayfish is its rotten smell.

Owner: Mary Kot

How To Tell If A Crayfish Is Dead?

Nobody wants to lose their pet crayfish. Sometimes, beginners do not realize for a long period that their crayfish is no more. That’s why you should know about some signs to tell your crayfish is dead.

1. Lack Of Movement

The physical activity of any creatures stops when they are dead. Since the blood circulation stops in a dead crayfish, it’ll not be able to move any organs.

If your crayfish is dead, you’ll see it still in a place for hours. However, crayfish may play dead for various reasons. You might get fooled in such a case when your crayfish is playing dead with no movement.

For this reason, you should look for other signs of death besides no movement in a crayfish.

2. Unresponsive To Stimuli

One of the most significant signs of a dead crayfish is its unresponsiveness to stimuli. You can try to poke your floating crayfish. Also, you can check for their response in light.

Sometimes, a crayfish may not move when it is molting. But, alive crayfish respond to touch, light, or other sensories. You might notice the slight movement of their antennas or tails in such cases. If your crayfish is dead, it’ll not show any movement.

3. Dull Coloration

A dead crayfish will start to lose its color gradually. You may notice your darker crayfish turning into dull coloration. Changing color is a prominent sign of something wrong with your crayfish.

4. Curled Tails

Another sign of a dead crayfish is its curled tail. The abdomen muscle of a dead crayfish contracts, which leads to curled tails.

5. Floating On Surface

If your crayfish is floating, there may remain several causes. It can be due to the molting or pre-molting phase. Otherwise, your crayfish may be dead.

6. Bad Smell

Lastly, your dead crayfish will start to stink badly. The odor will confirm that your crayfish is dead.

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If all signs of dead crayfish get matched, you should remove your floating crayfish from the tank.

Can You Eat Crawfish If It Died?

It’s entirely your taste preference whether you want to eat dead crayfish. There’s no restriction on eating dead crayfish.

But, expert chefs suggest not cooking the crayfish that are dead before boiling. Cooking dead crawfish may lessen the taste. Instead of eating dead crayfish, the chefs recommend boiling or cooking fresh crayfish.

Can A Crayfish Drown?

Since crayfish are aquatic creatures, you might be surprised to know about their drowning. Besides, these crustaceans can breathe underwater. So, the crayfish hobbyists often ask- can a crayfish drown?

The answer is yes! Crayfish can drown if they do not have adequate access to fresh water.

The anatomy of crayfish is so unique that they can breathe underwater through their gills. These specialized gills pull the oxygen from water into the bloodstream. In addition, these crustaceans can breathe air.

Like fully aquatic frogs and betta fish, crayfish can not come up to the surface to breathe air. Hence, it’s safe for crayfish to stay within only 6 inches of deeper water.

 If crayfish go down under deep water, these crawfish may suffocate due to lacking oxygen. As a result, crayfish will drown when the water isn’t properly aerated.

Owner: John Cottrell

Frequently Asked Questions

What to do with dead crayfish in fish tank?

When dealing with a dead crayfish in a fish tank, it’s important to take appropriate measures to maintain the health and cleanliness of the tank.

Here’s what you can do:

1. Remove the dead crayfish: Using a net or aquarium-safe tongs, carefully remove the dead crayfish from the fish tank. It’s essential to remove it promptly to prevent any decomposition that could harm the water quality.

2. Dispose of the crayfish: You have a few options for disposing of the dead crayfish. You can bury it in your garden if you have one, or you can wrap it in newspaper or a plastic bag and place it in the trash. Avoid flushing it down the toilet or disposing of it in bodies of water.

3. Monitor water parameters: After removing the dead crayfish, monitor the water parameters in your fish tank. A sudden death in the tank can lead to changes in water quality. Test the levels of ammonia, nitrite, nitrate, and pH to ensure they are within the appropriate range for your fish.

4. Perform a water change: If the water quality is affected, perform a partial water change to help restore balance. Replace a portion of the water, usually around 25-30%, with dechlorinated water of similar temperature and parameters to the existing tank water. This helps dilute any toxins that may have accumulated.

5. Observe remaining tank inhabitants: Keep a close eye on the remaining fish and other tank inhabitants. Monitor their behavior, appetite, and overall health. If you notice any signs of stress or illness, it’s important to take appropriate action, such as consulting a veterinarian or an experienced aquarist.

Why did my crayfish turn blue?

Crayfish can turn blue due to a variety of reasons.

One possible reason is molting, which is a natural process where crayfish shed their exoskeleton to grow. After molting, the crayfish’s new exoskeleton may appear blue before it hardens and turns back to its original color.

Another reason is diet, as crayfish that consume a low-fat diet lacking in carotenoids (vitamin A) may lose the ability to produce red and yellow exoskeletons, causing their exoskeletons to appear blue.

Additionally, seasonal changes in diet can also cause crayfish to change color, with crayfish ingesting more vitamin A during the summer months and thus appearing reddish-brown, and less vitamin A during the winter months and thus appearing more blue.

Why is my crayfish upside down?

Crayfish can be upside down due to a variety of reasons. One common reason is during their pre-molting stage, where they may flip over and remain motionless for a period of time. This behavior is natural and nothing to worry about.

However, if the crayfish remains upside down for an extended period of time, it could be a sign of illness, injury, or lack of oxygen in the water. In such cases, it is important to investigate the possible causes and take necessary steps to help the crayfish get back to its normal position.

Do crayfish die in freshwater?

Crayfish are generally well-adapted to freshwater environments and can thrive in them. They are naturally found in various freshwater habitats such as streams, rivers, lakes, and ponds.

However, like any living organism, crayfish can die in freshwater under certain circumstances, such as: poor water quality, diseases or infection, aggressive predators, lack of food source, etc.

Final Words

So, these are all the common reasons for the death of crayfish. As I’ve already said, crayfishes are generally very hardy creatures and they are not very demanding.

That being said, if the set up isn’t ideal or the water condition is poor, even a hardy creature like crayfish can die.

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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