The Miami Cave Crayfish (Procambarus milleri) is one the rarest crayfish species in the aquarium hobby. If you by chance buy one you will be surprised to find out how little is known about them.
Even more, the researchers stated that virtually nothing is known about this species’ natural life traits. Much of what is currently known about the species is based on aquarium observations. Once again, our hobby is ahead of science.
In this article, I have gathered all information about Procambarus milleri from German and Russian crayfish breeders. It covers all aspects, from natural habitat conditions and how they should be cared for within your aquarium, to dietary requirements and how to breed them.
Quick Notes about Procambarus Milleri
|Common Names||Miami Cave Crayfish, Cave crayfish, or Tangerine crayfish|
|Scientific Name||Procambarus milleri|
|Tank size (optimal)||10 gallons (~40 liters)|
|Size||up to 3 – 4 inches (8 – 10 cm) long|
|Optimal Temperature||71 – 75 °F (22 – 24 °C)|
|Optimal PH||7.0 – 8.0|
|Optimal GH||10 – 25|
|Diet||Omnivore / Carnivore|
|Life span||up to 4 years|
|Color Form||Yellow to red|
Habitat Procambarus Milleri
Procambarus milleri is only known from two localities in Dade County, Florida. This species is endemic to these places.
These crayfish are groundwater animals. They inhabit deep geological formations, greater than 16 ft (5 m) beneath the Rocky Glades, with voids of various dimensions that flood periodically but always contain water.
Description of Procambarus Milleri
Miami Cave Crayfish are relatively small species but they grow really fast. Generally, they grow only up to 3 – 4 inches (8 – 10 cm) long.
These crayfish are available in bright-colored morphs (yellow or red to yellow) that are dramatically different from their normal (mostly white with a little bit of yellow) wild-type coloration.
Note: Once again, this mutation comes from the crayfish being bred in captivity and not in the wild. There is no information on who, how, when, and where their yellow color morph was originated for the first time.
Difference Between Procambarus Milleri, Procambarus alleni, and Procarambus Clarkii
Unfortunately, it can be really hard to tell them apart when they are young. Basically, these species are identical almost in everything.
The problem is that Procambarus milleri is a very young species. Scientists suggest that this species was derived from a parental stock of Procambarus alleni and evolved after the aquifer was lowered in south Florida in the 1920s.
We can only see the difference once they are fully grown.
- Size. Procambarus milleri is the smallest one.
- Temper. Procambarus miller is the least aggressive.
Lifespan of Procambarus Milleri
Currently, there is no data available on the maximum lifespan for Procambarus milleri in the wild.
However, in captivity, these crayfish can live up to 3 – 4 years, if appropriately cared for.
Typical Behavior of Procambarus Milleri
Fully grown Procambarus milleri is one of the few types of crayfish that can be kept in a community tank relatively safely. They are not very aggressive as their bigger cousins (Blue crayfish, Red crayfish, Marbled crayfish, Cherax Destructor, etc.). It is recommended to keep one male and one or two females in the group.
Note: It does not mean that they are social. No, they can just tolerate high stocking densities better than most crayfish species.
Interestingly, these crayfish are the most aggressive when they are young (1 – 2.5 inches or 2.5 – 7 cm long). Unlike adults, they display a strong competition for resources.
Although these crayfish are perceived to be nocturnal due to their peak activity being after dusk, one of the best things about this species is that these crayfish are not timid animals. On the contrary, they are pretty active and outgoing. You will often see them crawling or sitting in the open.
Miami Cave Crayfish cannot be categorized as a primary burrower.
In the aquarium, they also like to move objects around. Overall, they can be pretty messy and destructive.
- Social: No
- Active: Yes
- Peaceful: Generally Yes (adults), No (juveniles)
- Burrowers: No (generally)
Feeding Procambarus Milleri
These crayfish are classified as opportunistic omnivores. It means that they will eat just about any food they manage to find on the bottom of your tank.
Nonetheless, observations indicated that these crayfish have a strong preference for high-protein food. For the best growth, feeds should contain protein at a level of at least 30 – 40 % of the diet.
Also, juveniles and pre-adults tended to eat more and show more interest into plant materials compared to adults. However, it does not mean that they should not be given high-protein food. It simply means that young eat A LOT because they grow very fast.
Suggested foods for your crayfish include:
- crushed snails,
- live bloodworms (they go crazy about them!)
- frozen bloodworms,
- black worms,
- dead fish or shrimp,
- artemia sp.,
- fish food (pellets, granules, flakes),
- Shrimp food (Hikari’s crustacean, Algae wafers – links to Amazon), etc.
You will need to find food that sinks to the bottom. In addition, it should not be too small, otherwise, it will be difficult to pick up.
- Diet Type: Omnivores / Carnivore.
- Food Preference: Mix of meats and vegetation.
- Feeding Frequency: 3 – 4 times a week for adults. Daily for juveniles.
- Leave their food for 12-24 hours before removing it. Leaves can be left for several days in the tank. Just make sure that whatever they do not consume in one day is removed to prevent water contamination.
- Check the burrows. Keep in mind that crayfish often drag and store food in their hiding spots for later consumption. Check them from time to time to prevent any bacterial contaminations.
- Diversity. Do not give them the same food all the time. Provide the various food items to diversify the diet. It will make them stronger and grow faster.
- Aggression. They become more aggressive when hungry. Keep in mind that protein plays a fundamental role in their life. If they do not get enough they also become aggressive and may even turn cannibalistic!
|Do not forget that also calcium plays a huge role in crayfish. Therefore, I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.|
- Indian Almond Leaves and Alder Cones in a Shrimp Tank.
- How to Blanch Сucumbers and Zucchini for Shrimp, Snails and Fish the Right Way.
Are Procambarus Milleri Plant Safe?
In their natural habitat, these crayfish live underwater in limestone caves, there are no plants there. Basically, this is not their food.
Therefore, adults usually do not eat plants that much, but they may cut, and shred them. However, pre-adult crayfish will definitely eat whatever plant you have in the tank.
Therefore, I would still not recommend keeping them in the planted tank, especially, with young crayfish.
The only viable options for this species are:
- plastic plants,
- floating plants,
- some cheap plants that you are ready to lose.
You can also read my articles:
Keeping and Housing Procambarus Milleri
Procambarus milleri is a pretty hardy species. Keeping them in a tank is not complicated because they do not have special water quality requirements.
These crayfish do not require a lot of space. So, a 5-gallon (20 liters) tank can house 1 adult crayfish. One male and 1 – 2 females may be kept together in the same enclosure of 10 gallons (40 liters).
Of course, having a larger tank is always preferable for the stability of water chemistry. In addition, it can be easier to make diverse areas for them to hide.
Important: Like all crayfish, they are known to be able to climb vertical surfaces, and often they use this ability to escape from any tank. So, a tight-fitting lid is essential.
Temperature The ideal water temperature for keeping Procambarus milleri is between the range of 71 – 75 °F (22 – 24 °C).
pH: Maintain optimal pH values between 7.0 – 8.0 for the crayfish to thrive in your freshwater aquarium.
Hardness: They will appreciate optimal GH between 10 – 20.
These crayfish are very adaptable and can live in tap water. All you need to do is to age your water for a few days to remove chlorine.
Keep in mind that “aging” does not remove chloramines. Therefore, if your city water has it you will have to use special products (water conditioners) to neutralize it. Because it is the only way to get rid of chloramines in the water.
Maintenance: Do 20 – 25 % water changes every week.
As long as you have got the filter that works great with the size of the tank you have got you will be fine.
Note: Sometimes adult crayfish may chip and chew on the sponge filter. Just keep that in mind.
Procambarus milleri lives in caves underwater. They used to live without light. Therefore, you may not even need one.
However, if you have plants, lighting should be adapted to their needs.
There is no need for a deep substrate. It can be 0.5 – 1 inches (1 – 2.5 cm) deep.
This way it will be easier to clean substrate after feeding them. Remember, they are messy and eat a lot especially when they are young.
Note: Over time, uneaten food will work its way into the substrate. Eventually, it will cause an ammonia spike. We do not want that.
Decorations and Hiding Places:
Do not forget that décor is not for you! It has another purpose.
Decorations provide hiding places (shelter and protection) and minimize their stress. This is especially crucial for the molting process. Cannibalism after molting can become a big problem.
Procambarus milleri will appreciate all types of leaves, rocks, driftwood, PVC pipes, plastic mesh, and other decorations to enrich the environment in your tank.
All crayfish have a rigid exoskeleton that protects their internal organs and prevents their growth. The old exoskeleton must be shed periodically (a process called molting or ecdysis) in order for them to grow and restore lost limbs.
During the first 6 months of their lives, Procambarus milleri molt every 2-3 weeks. After that, the molting cycle increases to 1 – 2 months. Fully grown individuals molt every 6 – 12 months. Generally, they do that to restore lost limbs.
Hobbyists noticed that this species in particular has additional signs of upcoming molt–white spots near the eyes (in the “temple” area of the crayfish). These spots become very saturated right before molting.
When crayfish is about to molt it starts looking for a place to hide. Otherwise, they can easily fall prey to their tankmates.
Sexing Procambarus Milleri
This species is sexually dimorphic.
- Claws. Males have much larger and longer claws than females.
- Shape. Females have a wide tail; their carapace is also slightly bigger.
- Abdomen. Males crayfish have two L-shaped appendages (semen transfer organs) behind their legs called claspers. The females have a circular semen receptacle between the bases of the last two pairs of walking legs.
Breeding Procambarus Milleri
Procambarus milleri is very easy to breed. All you need to do:
- keep the optimal ratio of males and females (1:3) and they will multiply into a large colony,
- provide enough food,
- give them a lot of hiding places.
Depending on the temperature, they reach maturity when they are about 4 – 6 months old. When a female is ready to mate, she will allow a male to approach, clamp her claws, and put her on the back.
Females usually carry anywhere between 10 and 30 eggs. In some cases, big females can have more eggs. The female uses her appendages to keep the eggs clean from dirt and well oxygenated.
The reproduction will only occur if water temperature remains above 68°F (20°C).
It usually takes from 6 – 8 weeks to hatch depending on temperature. While carrying eggs, females spend a lot of time hiding.
Procambarus milleri do not have larval stages.
Newly hatched young are incapable of living separately from the mother for the first several days.
Hatchlings would occasionally drop from the motherʼs abdomen, crawl
freely around the aquarium, and then climb back onto her body beneath her abdomen.
It takes them a couple of molts to get bigger and leave their mother. From now on, they are completely independent.
|One of the best things about this species is that adult crayfish do not eat their young. If they have enough food and places to hide, cannibalism is pretty rare even between juveniles.|
At first, juveniles prefer artemia to eat but in general, they can feed on the same foods that have been offered to the adults. It just needs to be in smaller proportions. Frequent feeding (1-2 times a day) is highly recommended.
Procambarus Milleri and Suitable Tankmates
The ideal situation for Procambarus milleri is a species tank. Nonetheless, many aquarists successfully keep them in community tanks.
Unlike other Procambarus species, these crayfish tend to become less aggressive as they age.
These crayfish can be kept with small and peaceful fish like:
- Neon tetras,
- Clown Killifish,
- Least Killifish,
- Dwarf swordtails, etc.
Important: No aggressive fish should be kept in the same tank with them. Bottom-dwelling (such as Ancistrus spp. Gastromyzon spp., Beaufortia spp. etc.), slow-moving, or fish with long fins (like Betta) will be the first ones to get hurt.
During my research, I have not found a single complaint! Shrimp can crawl and sit on them without any problems.
Procambarus milleri does not care about shrimp.
Eventually, Procambarus milleri will catch and eat all snails in the tank.
Bad Tank Mates:
- Larger or aggressive fish.
- Any other crayfish species.
- Other freshwater crab species.
- Dwarf frogs.
With their striking coloration, Procambarus milleri will definitely be an attractive addition to any freshwater aquarium.
Out of all Procambarus species, these crayfish are the most peaceful.
Caring for these crayfish is extremely easy for the most part, and the return on the investment is huge.