If you are considering keeping crayfish but do not know where to start or is it worth it at all? Within this introduction guide to the Crayfish care, I will attempt to answer all questions that you might have. I will cover every angle of Crayfish care and get you better acquainted with these magnificent creatures.
Crayfish are freshwater crustaceans, which are gaining more and more popularity in freshwater aquariums. These strange and fascinating animals often display flashing bold, vivid colors – a masterful array of natural art and beauty.
Also known as Crawfish, Crawdads, and Mudbugs, they belong to an important group of aquatic animals called decapods. Which literally means “having 10 legs”.
Note: The group of decapods also includes shrimp, crabs, and lobsters.
Interesting fact: There have been recorded fossils found of crayfish that are over 100 million years old. They lived with dinosaurs!
Natural Habitat of the Crayfish
In the wild, they adapted to live in swamps, rivers, streams, lakes, and ponds. However, they are most suited to live in rivers and streams, where water currents supply abundant oxygen and food.
Behavior of the Crayfish
There are two types of crayfish behavior: hiding and burrowing.
Burrowing Crayfish can dig deep into the substrate and, basically, live in their burrows most of the time. Some Crayfish species prefer hiding instead of burrowing. Although you will see them often walking around the tank, they still tend to be most active at night. Night is the time when they are hunting for food. These fully aquatic species will seek shelter under driftwood, rocks, crevices, and under aquatic plants.
In general, Crayfish are aggressive. The only difference between species can be in the level of aggression. Some species can be extremely territorial and will not tolerate anything or anybody in the tank.
Description of the Crayfish
Crayfish have segmented bodies, outer shells or exoskeletons and paired jointed limbs. The hard outer shell or exoskeleton of the Crayfish is made of calcium carbonate extracted from the water and secreted in layers.
Like fish, they breathe through gills. However, they can also live extended periods of time out of the water as long as their bodies are damp and their gills are wet. In addition, they have the ability to filter water through their gills and collect food items out of that water.
They walk forward and move backward only when swimming by contracting their abdomen muscles.
The average lifespan for Crayfish is about 3 years. Although some Crayfish species may live for a decade or even more.
They come in a variety of stunning colors shapes and sizes. For example, Dwarf Mexican Crayfishes (read my guide about Cambarellus patzcuarensis) rarely grow larger than 2 inches. While the Marbled crayfish can grow up to 5 inches (read more about Marbled crayfish).
Fact: Generally, crayfish come in different variations of blue, white and red color. However, red is the more common type and white is the least.
Crayfish and Molting
All crayfish have a protective exoskeleton made up of chitin. This limestone suit of armor helps to provide protection against predators. Unfortunately, this exoskeleton does not grow over time. Eventually forcing them to molt and revealing a soft new exoskeleton underneath that will solidify over time. All crayfish, crabs, and shrimp species grow by shedding or molting their exoskeletons. There are no exceptions.
During this molting period, crayfish are called soft-shells because their exoskeleton is somewhat soft and rubbery. However, it soon hardens to its normal condition, which is when they are called hard-shells. Molting is a very stressful time for crayfish during which they are most vulnerable to predation.
Therefore, if you have 2 or more crayfish in the same tank, you will have to provide them with lots and lots of hiding places.
Crayfish molt many times, from when they are hatched through the first year of life. For example, baby crayfish can molt once per few days, while juveniles usually molt once per 2 – 3 weeks. But as adults, they will molt only once or twice per year.
Tip: Do not remove their old exoskeleton. They will eat it later to recover the calcium.
Fact: Crayfish have two limestone grains in their stomachs, which fill the new forming exoskeleton with calcium.
You can learn more about molting in my article ”Aquarium: Molting Process and Metabolism of the Dwarf Shrimp”. The principle is the same with any Crayfish.
Biology of the Crayfish
Crayfish have two main body parts:
- The cephalothorax (the head and chest region)
- The abdomen. This part of the Crayfish is mistakenly often referred to as the tail. The abdomen contains a unique muscle structure that allows the crayfish to swim backward very rapidly through the water.
Crayfish have two large pinchers or claws, which primarily fulfill 3 roles: feeding, mating, and fighting. Besides the claws, they also have 4 pairs of walking legs. The first two pairs of walking legs are tipped with small pinchers, which the crayfish uses for grooming, food manipulation, and movement. The eyes of the crayfish are on stalks, which extend above the head to provide a wide view of its surroundings.
- They have good eyesight. Each eye comprises thousands of tiny structures, each functioning as a separate eye and give the crayfish a mosaic view of its world much like that of an insect.
- The two antenna and shorter and ten mules are used for touch and smell.
- Crayfish breathe through their gills (that are located underneath the exoskeleton) which extract oxygen from the water. They can also breathe air as long as their gills remain wet.
- Crayfish have a remarkable ability to regenerate lost limbs. Therefore, do not worry if one of your crayfish will lose a claw or a leg during the fight. They will regrow it after a molt or two.
- The males clearly display much larger claws than females
- The males tend to have narrower tails compared to females.
- However, the main way to tell them apart is to look at the underside base of the tail. The male crayfish has two very prominent abdominal limbs or sperm transfer organs that extend between the walking legs. The female crayfish has a circular sperm receptacle between the bases of the last two pairs of walking legs.
In my opinion, Crayfish are an amazing animal because they eat such a wide variety of organisms and it is hard to pinpoint another animal that consumes so many different food sources.
For example, their menu includes animal flesh (fresh or rotten), aquatic plants and leaves (fresh or rotten), single-celled plants, biofilm, detritus, algae, all kinds of insects or worms. If it can be eaten, your Crayfish will eat it. They are excellent scavengers. Crayfish will clean your tank with pleasure.
Blanched vegetables (lettuce, carrots, zucchini, etc) are also welcome! Read more “How to Blanch Сucumbers and Zucchini for Shrimp, Snails and Fish the Right Way”.
Depending on the species, Crayfish can also be a great or just decent hunter (predator). Be very careful with the tankmates!
Crayfish are not plant safe! They will eat and uproot everything in the tank. Therefore, the best choice will be to have floater plants or cheap ones.
Note: The only species that you can keep with plants is Dwarf Mexican Crayfishes.
Like all snails, shrimp, and crabs, crayfish also require a lot of calcium for their exoskeleton.
Keeping and Caring for Crayfish
Crayfish are pretty hardy animals and easy to care for. They are super simple to feed and breeding is almost guaranteed! All these qualities make them an ideal choice for a beginner aquarium.
Except for the tank size, their requirements are minimal. In general, crayfish need a 20-gallon plus aquarium and the most important factor is the floor space.
They like pH 7 or higher. They can tolerate a wide range of GH (3 – 18) and KH (3 – 15). Tank temperature can be around 22 C (~72 F). So, you do not need a heater.
If you want to provide them with the best water conditions then using R/O water (reverse osmosis) is advisable but not essential. You can buy RO-DI units from Amazon and connect to most home faucets without the need for plumbing.
Use an aquarium pump. It will agitate the surface of the water and dissolve oxygen into the water. Crayfish will not mind against the gentle flow in the tank but it is not necessary as well.
They are nocturnal creatures, so there is no need for bright light. Nonetheless, if you have plants you will need them to help grow the plants. For example, LED lights with the nightlight mode.
Note: As I have said earlier, add plants with caution, crayfish are omnivorous so they will eat any vegetation they can get across.
Substrate and Decorations
Sand and small gravel of approximately 2 – 4 inches or 5 – 10 cm deep are the best choice. Crayfish like to dig, sift and rearrange everything to their liking.
Tip: Even if you have bought pre-washed sand or gravel, I would strongly advise you to give it a few rinses before adding it to your tank.
Provide your crayfish with hiding places to make them feel more secure. Add some driftwood, cholla wood, rocks, etc. for that. Natural decorations work really great for crustaceans. Ensure the driftwood is washed, cleaned and soaked. You can read more about it in “Driftwood in Shrimp Tank”.
Tip: If you are planning to have a budget setup for your crayfish, use PVC pipes. They are dirty cheap and crayfish love them! The only downside is the way they look.
In addition, I would like to mention that most crayfish species in our hobby do not need paludarium (aquarium that has both terrestrial and aquatic elements). However, if the size of your tank allows you can try to make one. Although your crayfish will appreciate it, I will repeat once again – you do not have to do that. I am just listing different options.
Once you have the correct size tank and the correct setup, you will need to cycle your tank and achieve the water parameters and temperature that Crayfish prefer.
Important: Crayfish are excellent escape artists. Therefore, you need to hide or protect all cables in the tank.
Tank Equipment (links to check the price on Amazon)
Do not forget to acclimate them before putting in your tank. Read my article “How I Drip Acclimate Shrimp and Why”. It is the same principle for the crayfish.
Be careful with copper (read more info about it) and you should not have any problem with them.
In nature, males fight for the right for the female. Crayfish can usually reproduce after they reached 3 to 6 months of age depending on food availability and water temperature. Therefore, to breed crayfish in the tank, I would advise feeding them a rich diet for a couple of weeks.
During mating, the male crayfish turns the female over on her back and deposited sperm into the females sperm receptacle where it is stored until she is ready to lay her eggs.
The fertilized eggs, which usually number from dozens into the hundreds, become attached to small appendages called swimmerets located under the abdomen of a female.
Incubation is directly dependent upon temperature. In most cases, it can take anywhere from a few weeks to 2 months for the eggs to develop and hatch in temperatures about 20C (~70F).
For some crayfish species, newly hatched young are incapable of living separately from the female. They can stay with her (also under the abdomen) for up to several weeks. Scientists say that there are the pheromones that the female crayfish secretes. These pheromones have two functions:
- Encourages the female to protect the
- Prevents cannibalism or else they are going to be eaten by the mother.
It is strongly advisable to provide lots of hiding places for the babies. The point is that crayfish babies are also aggressive and can turn against each other. You will also have to remove from the aquarium or remove the babies into a smaller hatching tank where they can be raised safely.
Regarding feeding, pick whatever you like. For example, you can give them Hikari Crab Cuisine Rapidly Sinking Sticks (link to check the price on Amazon).
Tip: Crush it in a coffee grinder first. You need small pieces, not a powder.
Crayfish and Suitable Tank Mates
There are so many questions about – can I keep crayfish with this fish or that fish? Can I keep crayfish with frogs? Can I keep them with snails? Are crayfish suitable for a community aquarium?
Well, the short answer is that due to the fact that they are territorial and aggressive, the best tank mate recommendations for them are none! Crayfish really are best kept in the same species only tank.
Keep in mind that crayfish is an opportunistic omnivore. They will eat absolutely anything they can catch (fish, snails, shrimp, frogs, and even other crayfish). Therefore, NO. It will not be a good idea to keep crayfish with anybody in the tank.
Of course, we can find some examples where people managed to keep aggressive species together. Nevertheless, remember, if it works for them it does not mean that it will work for you!
Large and aggressive fish (like loaches or puffers) can eat or harm your crayfish. While small fish will be their prey. If you are willing to take your chances, I can advise to pick only top-level swimmers and add plenty of hiding places. Of course, it will increase their chances of survival but in 99% you will lose a lot of fish anyway. Personally, it is not worth the risk.
Note: The safest crayfish is Dwarf Mexican Crayfish.
In conclusion, I would only have to say that crayfish species are amazing creatures. They are easy to keep and breed in a home aquarium. Most of them have wonderful coloring and eat just about anything you feed them! Crayfish will help to clean the water in your tank by feeding on algae, bacteria, and decaying materials.
Although they do not suit community aquariums or planted tanks, they will still definitely be one of the most interesting and colorful aquatic inhabitants to house.