How Much Water Do I Need For A Crayfish Tank?

If you are setting up a crayfish tank for the first time, you can easily get confused about the amount of water. There is so much information, and all seem to tell a different story. I know I really got confused! I don’t want you to fall in the same place. So, here’s what you need to know:

You can fill up the whole crayfish tank with water if it has enough aeration. If there isn’t any aeration system, then leave a few inches of water from the top. Also, make sure the crayfish can get above the water level.

I know the above answer needs a thorough explanation. So, let’s dive in!

The Amount Of Water Crayfish Needs: 3 Cases

One important thing you need to keep in mind when keeping crayfish is that crayfish need oxygen in the water. Oxygen is vital for them; otherwise, they can drown themselves.

Some oxygen is dissolved in the water naturally. But this is not enough for a crayfish, especially if it lives in a deep tank. So, we’ll have to add oxygen to the water or let the crayfish have access to oxygen.

Adding Oxygen To The Water:

To increase the amount of dissolved oxygen in the water, we need to do one simple thing. It is increasing the amount of surface agitation. The more surface agitation there is, the more oxygen will get dissolved into the water.

But, you may ask, how can I increase the surface agitation?

Actually, it is pretty simple. Just get your hands on a decent air pump and air stone. Set up the air stone with the pump and leave it on 24/7. The bubbles from the air stone reach the surface of the water and agitate it. As a result, more oxygen dissolves into the water. This ultimately results in a healthier tank for crayfish.

Letting The Crayfish Have Access To Oxygen

Now, if you don’t have an air pump or don’t want to buy one, there is another option you can consider. In this option, we’ll have to set up the habitat so that the crayfish can rise above the water level if necessary.

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We can simply accomplish this by placing a large stone in the middle of the aquarium. Make sure the top portion of the stone rises above the water level.

So, if the oxygen level in the water becomes too low, the crayfish can simply crawl to the top of the stone to obtain oxygen.

Now that we understand these two principles let’s discuss how much water you actually need to put in the crayfish tank.

1. Tank With Aerator

In this case, your crayfish tank has an aeration system. So, there is an air pump pumping out air through an air stone 24/7. As a result, there is plenty of surface agitation, which results in more oxygen being dissolved into the water.

So, you can nearly fill up the tank with water. However, I’ll suggest to keep about 2 inches of free space from the top of the tank.

Crayfishes are an amazing escape artist. If you fill the whole tank with water, they can easily escape. So, just for safety, leave at least 2 inches of free space from the top.

If you are keeping a larger species of crayfish (Cherax Sp.), feel free to leave more empty space from the top of the tank. However, make sure the crayfish can’t escape using anything.

One important thing is to keep the airstone in the middle of the tank. I have heard stories that the crayfish escaped using the inline tube of the air stone. So, if you are using an air stone, it is extremely important to have a proper lid cover for your tank.

2. Tank Without Aerator

In this case, you don’t have any aeration system. So, the crayfish needs to have access to air so it can get oxygen if necessary.

You need something in the tank that the crayfish can use to get out of the water. In my case, large stones are pretty good for this purpose. They also look natural and work as a natural hiding place for the crayfish. You can also use large bogwoods or driftwoods if you have access to them.

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Keep in mind that some portion of the stone or wood needs to be above the water level. As a result, the crayfish can crawl to the top of the stone or wood and access fresh oxygen.

So, the water level can be much lower than the first case. Adjust the water level according to the height of the wood/stone.

Also, before using any stone or wood, be sure to treat these for any germs or dirt. Only use these after they are safe for aquariums. Here’s how you can treat wood/stone for using in the aquarium:

  • First, clean the wood/stone under running water.
  • You can treat the wood/stone with a hydrogen peroxide solution. It ensures all the germs/bacteria are dead.
  • For added safety, I also like to boil my wood and stones for 3-4 hours to ensure they are completely safe for my aquarium.

3. My Favorite Approach

This is my favorite approach. In this case, I just combine the above two. When keeping pets, I am always extra careful and want to provide the best environment for my pets.

So, I always keep an air pump ON in my crayfish tank. I also have some large stones so the crayfish can easily get out of the water if it wants. I feel this setup is more comfortable for the crayfish and resembles their natural environment.

If you want a decent air pump, check this one out. This pump is from Tetra Whisper. There are multiple sizes available for multiple sized tanks. Just choose the one that suits your budget and tank size.

If you have a 10 gallon tank, I’ll take the one that is powerful enough for a 15 or 20 gallon tank.

Is Just An Aeration System Enough?

Sadly, just an aeration system is not enough for a proper crayfish tank. For any living inhabitant inside an aquarium, you’ll need proper filtration.

Filtration ensures the water does not contain ammonia, nitrite, or other harmful elements, which is crucial for crayfish.

For a crayfish only tank, I like to use a Hang On Back filtration system. They are comparatively cheaper than a canister filtration system, however more effective than a sponge filter.

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Also, sponge filter may allow the crayfish to escape from the tank. So, I think HOBs are better for a 10-20 gallon crayfish tank.

I like the HOB filter from Marineland Penguin. They are large enough to hold a good amount of biological filtration media. When it comes to filtration, the more biological filter media the filter can hold, the better its filtration will be.

So, try to go with a moderately sized HOB filter for your crayfish tank. Also, it is a good idea to purchase a bag of ceramic ring/bio balls or other biological filter media separately.

Fill up the HOB with these biological filter media as much as possible. This way, you’ll have a proper filtration system for your crayfish.

And your crayfish will Thank You for that!

Do Crayfish Need To Come Out Of Water?

If there isn’t enough oxygen in the water, then the crayfish needs to come out of the water. Otherwise, the crayfish can drown itself.

So, either use an air pump in your crayfish tank or let it breathe fresh oxygen from the air.

How To Make The Water Safe For Crayfish?

Before using water directly from the tap to your crayfish tank, you need to make it safe for the crayfish. This is not only for crayfish, for any living animal, you need to make sure the tap water is safe for them.

In most places, tap water contains chlorine and chloramine, which are harmful to living aquarium creatures. So, we need to treat the tap water to make it free from chlorine and chloramine.

A quick way is to use a safe water conditioner/dechlorinator. I like the Seachem Prime. It is world-renowned and reputed, so you can definitely trust it.

Another option is to use aged water. Fill your bucket with water and leave it there for 24-48 hours. It will be better if you leave an air stone ON inside the bucket.

After about 24-48 hours, the water will be completely free from chlorine. However, aging water doesn’t necessarily free it from chloramine. So, if your tap water contains chloramine, it will be better to use a water conditioner instead.

For your convenience, I am mentioning 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.
Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of 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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