Marie is a lover of everything about and inside of aquariums. Among other friendly creatures, she has a turtle that she adores.
Dwarf Crayfish Care
Out of all the crayfish available in the pet market, Cajun Dwarf crayfish (Cambarellus shufeldtii) are the most adorable because of their miniature size. I have kept and successfully bred Cajuns for the last year and a half, and I will explain what I have done to keep these tiny animals alive and healthy.
Appearance, Behavior, and Origin
Cajun Dwarf crayfish are a native crustacean of the southern United States, and the average adult is only one inch (2.54 cm), although some can be slightly longer. They can be plain beige, mottled grey/brown, dark, or bare brown stripes. While their colors are neutral and earth-tone, they come in a variety of patterns, even among siblings.
Not only are they ideal for small tanks, but they are the most peaceful species of crayfish, getting along with each other and small fish. Unlike most crayfish, they will not destroy live plants as they are too small to cause damage.
Cajuns also molt like all crayfish, which means you will find hollow versions of them from time to time. It can be alarming for first-time crayfish owners, but as long as you can see through the remains, I can assure you it is just their old shells. If you ever catch your little cray in the act of molting, do not disturb them, including turning on/off the lights. Adding stress to a molting crayfish can result in injury or death.
These little guys have big personalities. Despite their tiny size, they will try to intimidate you with raised pincers. They'll also recognize you as "bringer of food" and will come out to greet you, waiting for food to be dropped in their tank. Sometimes they grab food and hurry away to a shelter, or they'll stay in the open and munch. They will on occasion swim backward quickly—out of fear or, like a jellyfish, in order to get to a high place without having to climb.
- Like with all crustaceans, hard water (GH—high in mineral content) is crucial for their shells, particularly for brand new shells after a molt.
- Ideally, pH should be in the 7.4-8.4 ppm range. I suggest purchasing an API pH water test kit from Petco, Petsmart, or your local pet shop. If your pH from the tap is too low, add cuttlebone (found in the pet bird section) to the filter of the tank, which will increase the calcium content of the water. You could also try adding small fragments of limestone and cleaned eggshells, but the former is simpler and cheaper. Be sure to change out the cuttlebone every couple of months.
- In addition to keeping the mineral content high in the tank, make sure the water has plenty of oxygen. A filter (which is essential) will create ripples that oxygenate the water. Bubblers and plants will also increase the level of oxygen. Your Cajun Dwarf crayfish should not try to climb out of the water unless there isn’t enough oxygen underwater, although they do like to climb and sit on the leaves of plants underwater (I guess they like the view).
- Iodine is an essential element for molting found in the marine section of pet stores. Many sources claim that adding half the amount of iodine meant for saltwater can ensure a safe molt, but I have never added iodine to my tanks. Instead, I make sure they consume iodine in their diet, which I will go into later. However, I've never heard of ill effects from adding iodine to the water, except for accidental overdose.
- Because they come from warm southern waters, keep the temperature in the 70-80 degree Fahrenheit range (21-26 Celsius).
How to Set up the Tank
While these crayfish can live among each other—even being near each other in the open with no territorial disputes—you still need to provide many hiding places so your crays don’t feel overcrowded. They don’t like being around each other; they merely tolerate it. So in order to keep the peace, provide as many hiding places as there are crayfish, with the addition of two hiding spots so they have more options. These hiding places include:
- Cut PVC pipe
- Little caves/ornaments
- Plants (fake or real)
- Underneath internal filters
Gravel or Sand
Gravel should be small so there is no chance of them being crushed by the rocks. Average-size gravel in pet stores appears to be fine just as long as you keep an eye on what you are siphoning when performing a partial water change. Sand is also acceptable.
Crayfish generally do not like bright lights, which is why they should be kept in low lighting, or at the very least given many plants for coverage (real or fake).
These little guys are omnivorous, but they mostly eat veggies. I feed my crayfish once a day with one of the following:
- Ken's veggie sticks (several times per week—found online only)
- Thawed Frozen Bloodworms (Petco or Petsmart)
- Thawed and Shelled Frozen Peas
- Thawed Frozen raw pink salmon (available at Walmart)
- Crab Cuisine pellets (several times per week—Petco)
While I make Ken's veggie sticks and Crab Cuisine pellets their staple diet, I make sure they get a variety of raw, natural foods. Crayfish also like other vegetables, like carrots and zucchini.
Providing Calcium and Iodine
When looking for food for invertebrates, look for ingredients with calcium and iodine. While all pellets catered to crustaceans and invertebrates will have these nutrients (or should), give your crays raw food as well.
The following raw foods are high in iodine:
- Sea Vegetables (including kelp and dried seaweed, e.g. nori)
- Seafood (Cod, Shellfish, Shrimp)
- Certified Organic Eggs
- Baked Potato Skins
- Dark Leafy Greens (Spinach, Romaine Lettuce)
- Frozen Blood Worms
The following foods are high in calcium:
- White Beans
Avoid Copper Sulfate
When looking for food not intended for aquarium animals, be sure to watch out for the ingredient copper sulfate. Copper will harm inverts. Also, be wary of using foods with added salts or seasoning. The food must be as raw as nature provides it.
How Often Do You Feed Them?
I feed my crayfish once a day, and I feed them with a turkey baster to ensure everyone I can find gets their nutrition. This is a better practice when your crays have tank mates that can move faster than them.
The small size of the Cajun Dwarf crayfish has its pros and cons. Their small size means they are not a danger to small fish, but they can become prey to larger fish. A good rule of thumb is to select peaceful fish that could not possibly fit the 1-inch inverts in their mouth. Here is a list of fish safe for adult Cajuns:
- Fancy guppies
- Endler live bearers
- Cory catfish
- Sparking Gourmi
- Least Killifish (Heterandia formosa)
Any type of sucker fish (algae-eating fish) will be safe, including plecos. However, when deciding on tank mates, be sure the fish are non-aggressive and prefer hard water. For example, neon tetras (many types of tetras) prefer a lower pH. Also avoid fish with long flowing fins, like the betta fish, as the Cajuns may tear at his fins if there is ever a confrontation.
In addition to small, peaceful fish, all snails and shrimp are safe with Cajuns as well. I would not place amphibians or reptiles in the tank, no matter how small. The crayfish will either be dinner or they can scratch and cause a deadly infection in a frog's skin.
If you have several males and females and their diet, water quality, and environment are right, they will reproduce. Intercourse will look like an attack, with the male holding the female's pinchers so their bellies are facing each other. They may lie there holding onto each other for several minutes, sometimes exceeding 10-20 minutes. The male will eventually let go, and the male and female with go about like nothing ever happened.
Eventually, the female will have black eggs attached to her, underneath her tail. Nutrition and water quality are essential for babies to develop and survive. The pregnant female will also stay in hiding (for the most part) as the eggs develop, only coming out to eat, so I would place food near her hiding place.
When the babies hatch, there may be 10-20 that initially survive. They will stay close to mom for the first 1-2 days, then the babies have to fend for themselves. I would not worry about feeding them. They will survive on the tiniest amount of whatever you feed your crays.
Keeping the Babies Safe
If you want most of the babies to survive, you will need to remove all fish (even endler live bearers) from the tank, otherwise, they will be eaten. Removing all the babies will be impossible because they are so small and hard to see. Do not worry about the adult Cajuns. They express no interest in the babies.
The babies are so tiny that you will need to avoid gravel siphoning (any siphoning really, unless you do it at the near top) for at least a month. You must take your time performing partial water changes, as you don't want to accidentally suck up a baby in a container or in the siphon. Babies learn to swim and will occasionally fly up to the surface momentarily, so be careful.
They will triple in size after a month. By four months, they will be near the size of adults, although they usually don't mate until they are one year old.
Illnesses and Injuries
While I have never encountered this, crayfish can be affected by fungal and parasitic diseases. They can also inadvertently harm themselves during the molting process, such as getting a claw stuck in their molt. For all three issues, I only know of two safe treatments that should be used simultaneously:
- Perform an early partial water change to ensure the water is clean.
- Add dissolved aquarium salt (in water) directly onto the affected crayfish.
Enough freshwater aquarium salt can harm inverts. As a rule, you don't want to put more than one tablespoon of salt per five gallons of water. Just take a teaspoon of salt and put it in a container, add some aquarium water to it, and after a while use a turkey baster to suck up the dissolved salt water and release it (underwater) onto the ill crayfish. Aquarium salt will help prevent infection in injured claws, and it will kill parasites and fungus. Clean water will also reduce the chance of bacterial infections.
For crayfish with deformed/injured claws as a result of a bad molt (often linked to iodine deficiency), aside from water changes and adding dissolved salt water to the wound, I would let nature play itself out. I would not attempt amputation, nor would I try to help a crayfish out of his molt. This often leads to the crayfish panicking and wriggling himself out too soon, resulting in an injury. Only after a few days would I be tempted to help him out, but there are high risks to intervening with nature.
Cajun Dwarf Crayfish Care Isn't Hard
Cajun Dwarf crayfish care is no more complex than any other crayfish type. Just be sure they are kept with small, peaceful fish and have adequate nutrition in their diet and water.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
Jay Rowe on May 02, 2020:
Great information, thank you!