One of the most popular members of a freshwater tank, the Mexican Dwarf Crayfish will add life and color to your treasured aquarium. They look like tiny, tiny lobsters, and have a bright color to match.
Adding invertebrates to freshwater aquariums has become exceedingly popular of late, and these little creatures fit the bill nicely: they help clean your tank, look fabulous, and have dynamic yet peaceful personalities.
In this article, we will delve into the ins and outs of owning Mexican Dwarf Crayfish, or Cambarellus patzcuarensis. We’ll cover behavior, appearance, breeding, tank requirements, and more.
Table of Contents
Mexican Dwarf Crayfish Facts & Overview
|Care Level:||Moderate difficulty|
|Size:||~2 inches (5 cm)|
|Minimum Tank Size:||5 gallons (10 is better)|
|Tank Set-Up:||Freshwater, pH 6-8|
|Compatibility:||Keep away from large fish and crayfish|
|Temperature:||Kee60° - 75° F (16° - 24° C)|
Mexican Dwarf Crayfish, or Cambarellus patzcuarensis, is as the name suggests, mini versions of the crayfish you’re familiar with. Their appearance resembles a lobster; their size, a shrimp.
There are a few different varieties of the Mexican Dwarf Crayfish, and they have a number of different nicknames. The Cambarellus Patzcuarensis Orange crayfish shortens to CPO crayfish, so if you see that moniker, it likely refers to the brilliantly orange-colored crayfish we’re talking about here.
Note: There’s also a very cool-looking blue spotted one, the Blue Brazos Dwarf Crayfish (Cambarellus texanus) that is very similar in behavior and necessary care. So if you have that one, this article can also serve as a guide for you.
You may also hear these little orange guys being called Orange Dwarf Crayfish or Mini Mexican lobsters.
Regardless of what you call them, these dwarf crayfish are a good bet for your aquarium because they can survive well in myriad conditions, help clean your tank, and are the life of the aquarium with their distinct personalities.
The origin of the Mexican Dwarf Crayfish is also revealed in its name – these guys hail from Mexico and are also found in the southern U.S., usually in small rivers and streams, as wells as lakes and ponds. They prefer shallow, slow-moving water with lush plant life.
Although the Mexican mini lobster adapts easily to different water situations, there is a modicum of difficulty involved in adding them to your aquarium; for best success, make sure your tank has a good filter and that you have cycled it before adding the new dwarf crayfish.
Note: You should cycle your tank in advance of any new addition to your freshwater aquarium.
If you do that and follow the instructions later in this article about appropriate tankmates, you should be able to enjoy your Mexican Dwarf Crayfish for the normal 2-3 year lifespan of these creatures in captivity.
You might remember reading in some of our other guides that crayfish are a no-no for community tanks, particularly tanks with smaller creatures. That is true of the larger crayfish; these dwarf crayfish, however, pose little threat to your other tank community members.
Like most species, humans included, they may attack smaller creatures, so shrimp, snails, and tiny shrimp may be at risk, but in general, Mexican Dwarf Crayfish are pretty tranquil.
To really keep them happy, make sure to surround Mexican Dwarf Crayfish with the habitat they are used to in their native environments, such as plants, rocks, and wood; these features allow them to hide and to play.
Although Mexican Dwarf Crayfish love to hide in caves and around rocks and plants, they also enjoy exploring around their environment; you’ll enjoy watching them explore. Those hiding places are necessary, though, to protect them while they are molting and vulnerable.
Females also need places to lay low while they’re tending to their eggs, as do baby dwarf crayfish, who are totally defenseless.
But aside from these times when they are more at risk, you’ll see that the Mexican Dwarf Crayfish are amiable characters who might just show off their chelae (claws) to you, and enjoy hanging out with each other and sometimes with other fish.
Young dwarf crayfish molt a lot – 3 to 4 times a week! The molting process allows them to regenerate lost limbs. Once they get older, the Mexican Dwarf Crayfish molt once or twice a year. Either way, after they molt, the dwarf crayfish bodies are very soft, leaving them at risk for injury and death.
How can you tell that your dwarf crayfish has molted? You’ll see their tiny little exoskeletons scattered along the bottom of your tank. Don’t worry about cleaning them out of the tank – they’ll munch on the shells, which are a good source of calcium.
The bright orange color of the Mexican Dwarf Crayfish really stands out in your community aquarium, and sometimes even has red hues. They also have darker orange stripes and spots on the top of their bodies,
We mentioned before that these little guys look like miniature lobsters, with a hard shell encased body and a longer tail, which makes them great swimmers. With 19 pairs of limbs across the span of a 2-inch body, you can see why they molt so often. The Mexican Dwarf Crayfish is all legs!
In addition to 19 limbs, they have antennae that help them smell food and explore their surroundings. They also have black eyes that bug out.
The Mexican Dwarf Crayfish doesn’t grow longer than 2 inches (5.1 cm) and usually at a full-size range between 1.6 and 2 inches (4.06 to 5.1 cm).
As a comparison, non-dwarf crayfish is 6.9 inches (17.5 cm), about 3 times larger than the Mexican Dwarf Crayfish.
Mexican Dwarf Crayfish eggs are dark brown in color. The babies, which hatch as baby crayfish, not larvae, are less than an inch long, or about 2 mm.
Distinguishing between males and females
The pleopods, which are the limbs along the abdomen, differ in males and females. There are 5 pleopods, and the first pair is soft in the female and stiffer in the males.
Mexican Dwarf Crayfish are scavengers and are not super picky about what they eat. They’re omnivores and will consume plants and vegetables as well as live food like worms and brine shrimp.
Pro tip: Make sure to clean and blanch any vegetables before feeding them to the Mexican Dwarf Crayfish.
They will also eat food pellets and algae wafers. As we mentioned before, they consume their own exoskeletons after molting, and as a point of information and warning, they are also cannibals that will eat their young.
Warning: During gestation, you might consider moving the Mexican Dwarf Crayfish mother and her eggs into another tank until they hatch and mature.
Like other bottom scavengers, Mexican Dwarf Crayfish will dine on fish leftovers and waste, and even their deceased tank mate, so they’re cleaning the biome while they are getting nourishment. Be careful not to overfeed your tank, as that impacts the water quality, which is harmful to all the life in your aquarium community.
They’re not so interested in mid- and top-dwelling creatures like daphnia and mosquito larvae, so stick to feeding the bottom dwellers. Remember, the Mexican Dwarf Crayfish don’t move too fast, so they won’t catch and consume tankmates faster than a snail.
- vegetables, like peas, cucumbers, and zucchini
- brine shrimp
- black worms
- algae wafers
Helpful tip: We’ve said this in other guides, but we can’t repeat it enough. Make sure to check that nothing you add to your aquarium community has any copper in it. Copper is deadly to invertebrate
Habitat and Tank Conditions
You want to make sure that your Mexican Dwarf Crayfish have enough room to freely explore your aquarium community, especially if you’re keeping multiple Dwarf Crayfish.
As you would do with any freshwater species, you want to make sure you have a decent filter and cycle the tank before adding the Mexican Dwarf Crayfish to your community.
They are adaptable to many habitats but keep in mind that they are tiny, so you should create conditions in which they’ll thrive, such as providing them with hiding places and keeping the tank free of larger creatures that might see them as a midday snack.
As stated above, invest in a quality filter for your new clawed friends. A sponge filter or hang on back (HOB) filter would both work to protect the Mexican Dwarf Crayfish from ammonia and nitrates, both of which negatively impact Dwarf Crayfish.
Remember that Mexican Dwarf Crayfish are accustomed to slow-moving currents, so monitor the filter to ensure that it’s not creating currents that are too strong for the Dwarf Crayfish. Also, make sure the intake filter is covered so you don’t lose any dwarf crayfish.
As a reminder, be sure your aquarium is well-stocked with plants, rocks, caves, and wood so that your Mexican Dwarf Crayfish can explore to their heart’s content while being protected from risk and harm.
Choose either gravel or sand line to the bottom of the tank to promote optimum conditions for your Mexican Dwarf Crayfish.
As you’ll see below, there is some variation in the water conditions needed to maintain healthy Mexican Dwarf Crayfish.
Mexican Dwarf Crayfish need a pH level in the range of 6.0 to 8.0. If you remember their natural habitat of southern lakes and rivers, you won’t be surprised that they prefer a temperature range of 60° – 75° F (16° – 24° C)
As for water hardness, Carbon Hardness, commonly known as KH, should be between 6 – 12. Total Dissolved Solids (TDS) should measure 100 – 500.
The minimum tank size for Mexican Dwarf Crayfish is 5 gallons, but a 10-gallon tank is necessary if you’re housing multiples and you have other members in your aquarium community.
Aquarium enthusiasts prefer to have a community that incorporates topwater fish; since Dwarf Crayfish mostly hang out at the bottom of the tank, there is less of a chance that they’ll encounter each other and engage in disputes.
Large and/or aggressive fish and other creatures are not a good fit for Mexican Dwarf Crayfish. A full-sized Crayfish will surely cannibalize the Orange Dwarf, and Cichlids are likely to devour them.
Encounters with Smaller Creatures
Mexican Dwarf Crayfish are usually pretty peaceful, but they do have their own personalities, so it’s possible you’ll find one that is territorial or more aggressive. Also, they sometimes get a little bolder when they’re in a group.
If you have dwarf shrimp or small snails, they may be a target of Mexican Dwarf crayfish.
Mexican Dwarf Crayfish tend to do OK with smaller fish that are fast-moving, like rainbow fish, danios, and neon tetras, but they do hunt for food, so we can’t rule out the small possibility that they’ll try to pinch a fish fin with those tiny claws. But they don’t eat fish.
Better tankmates for dwarf crayfish:
- Celestial Pearl Danio
- Sparkling Gourami
- Chili Rasbora
- Harlequin Rasbora
- Congo Tetra
- Ember Tetra
- Neon Tetra
- Rummy Nose Tetra
The average lifespan of Mexican Dwarf Crayfish is 2-3 years. To maximize their chances of the longest life possible, provide them with a high-quality environment as described in the last section. Make sure the aquarium water meets the appropriate specifications and that they have a plethora of habitat enhancements.
Do regular tank checks and maintenance, and provide them with a varied diet of vegetables, plants, and sufficient protein.
Mexican Dwarf Crayfish are thankfully not affected by ICH*, a parasite recognizable by the white spots on the fish it inhabits. However, many treatments for ICH contain copper, which is deadly to Mexican Dwarf Crayfish. If you are treating fish for this disease, make sure you check the label before adding it to your crayfish-inhabited tank.
*The condition of ICH (Ichthyophthirius multifiliis) infection is known as ICH, Ick, and white spot disease.
Crayfish Plague, on the other hand, is treacherous to crayfish and every invertebrate in your aquarium. Crayfish Plague is caused by water mold, but it’s not a disease that will develop in your aquarium community. Only if you introduce an already-infected crayfish into your tank will you have trouble.
Crayfish Plague is dangerously contagious, so make sure to avoid adding wild crayfish to your already established aquarium community.
Stress and Well Being
During times of molting, breeding, and threats, as well as less than ideal conditions, Mexican Dwarf Crayfish can experience increased stress, which is detrimental to their ability to thrive and live to maximum lifespan. Next, we’ll talk about the best community members for your Mexican Dwarf Crayfish.
No special measures are necessary for breeding Mexican Dwarf Crayfish. As long as you have a female and a male, you’re good to go.
Breeding takes place when the male uses his chelae to pin the female on her back for up to 20 minutes, culminating in the deposit of sperm into the female. However, fertilization does not take place at this time. She carries the eggs for a period of 1-4 weeks, after which the female Mexican Dwarf Crayfish lays 20-60 dark brown-colored eggs in a safe, covered area.
After the eggs are laid, she folds her tail under her body, fertilizing the eggs and at the same time forming a mucus sack around the eggs for protection. She cleans the eggs by using her swimmerets, which are the limbs below the tail. By pushing water to the eggs, the crayfish mama removes dirt and keeps oxygen levels sufficient.
Approximately 3 to 4 weeks after being laid, the baby crayfish emerge from their eggs. After hatching, the babies stay with their mother until they are ready to survive on their own, about 3-4 months of age.
Remember that these baby Mexican Dwarf Crayfish, less than an inch long, are extremely vulnerable, so if you don’t have the capacity to put the mama and babies in a separate tank during the growth period, make sure to include lots of small places for the developing dwarf crayfish to hide. Mitigating risk to these tiny creatures will greatly increase their chance of survival.
When feeding the baby crayfish, you should deposit food in several areas of the tank to ensure that they have an opportunity to partake in the meals. They can eat the same diet as the adult dwarf crayfish, and will also eat waste and leftovers on the tank substrate, but since they are hatchlings, they may not get there fast enough.
Is Mexican Dwarf Crayfish Right for Your Aquarium?
The orange hue of the Mexican Dwarf Crayfish really makes your community aquarium pop. In addition, they’re fun to have in the tank, as they often display bravado by clicking their claws for show.
These dwarf crayfish are generally peaceful and agreeable invertebrates, and they help keep your tank clean.
Because they’re so small, they don’t pose much risk to other community members, although you may want to hold off on adding them to a tank that has dwarf shrimp or snails.
However, because they’re so small, larger creatures may prey on them. Therefore, you’ll have to evaluate the benefits and/or risks of adding these tiny crayfish to your established community.
If you’re currently planning on establishing an aquarium, Mexican Dwarf Crayfish would be a great centerpiece to build a community around.
Do you think Mexican Dwarf Crayfish are an exciting addition to your aquarium community? We’d love to hear from you in the comments below!