Thai Micro Crab – A Complete Guide

Thank you for visiting! By the way… any links on this page that lead to products on Amazon and other stores/partners are affiliate links Aquarium Store Depot earns a commission if you make a purchase.

The Thai Micro Crab is the latest craze in nano tanks. These small yet peaceful freshwater crustaceans hail from Thailand and make an exciting addition to any home aquarium. Here, we’ll explore what these little creatures eat, as well as offer insights into their fascinating habits in order that you may provide them with a happy habitat.

Key Takeaways

  • Thai Micro Crabs originate from the Tha Chin River in Thailand and grow to 0.4 inches
  • Provide a suitable environment with a temperature between 70°F and 80°F, pH range of 6.5-7.5, hardness range of 2-10 dGH & sufficient filtration
  • Feed them a balanced diet & choose peaceful tankmates like cherry shrimp, pygmy corydoras or tiny fish
  • They are very shy and nocturnal in nature

Species Overview

Scientific NameLimnopilos naiyanetri
Common NamesThai Micro Crab, Panzer Crab, Pillbox Crab, Pill box Crab
OriginThailand (specifically in the Chao Phraya River basin)
Care LevelModerate
ActivityMostly active during the night (nocturnal)
Life Span1 year
Tank LevelBottom and on plants and decor
Minimum Tank Size5 gallons (18 liters)
Temperature Range68-78°F (20-25°C)
Water Hardness3-12 dKH
pH Range6.5-7.5
Filtration/Water FlowSlow to Moderate
Water TypeFreshwater Tanks
BreedingEgg layer
Difficulty to BreedDifficult
CompatibilityCommunity Tanks
OK, for Planted Tanks?Yes

Understanding Them

Thai Micro Crabs, also known as Thai Micro Spider Crab, are a species of small crustaceans native to Thailand. Appealing due to their peaceful temperament and distinct look, they make great additions to nano tanks in an aquarium setting. Another crab species that shares similar characteristics with the Thai micro spider crabs is Laos’ own variation: The Laos Micro Spider Crab.

These two breeds both go through molting processes where water fills up within its carapace, which results in separation and cracking open of its exoskeleton while the body remains soft before hardening over time days later – this process is shared by other members from across all types of crab.

Origin And Habitat

Thai Micro Crabs, also known as Laos Micro Spider Crabs, originate from the Tha Chin River in Thailand. They are peaceful and small creatures that can coexist with dwarf shrimp and thrive in a densely planted tank resembling their natural habitat. Proper filtration is key to maintaining water parameters and ensuring they live long, healthy lives – even tanks of 5 gallons (20 liters) size will suffice! Taking appropriate care by regularly monitoring conditions within the tank is essential for sustaining these tiny freshwater crabs.



Thai Micro Crabs, commonly referred to as false spider crab or freshwater spider crab, are one of the few fully aquatic crabs that can be kept in home aquariums. Their rounded bodies and unique patterned carapace help them blend into their environment while giving them an intriguing look for any tank owner’s enjoyment. With long legs equipped with filaments used to capture food particles floating around nearby they make great additions to nano tanks due solely to their size alone.

These Thai Micro Crabs have silvery-gray coloration which is mixed by brown, orange and white patterns, adding Camouflage capabilities. Plus, two pincers help maintain balance throughout the water column, making it easier for these micro crustaceans to catch snacks passing through its area of expertise! Not only does this combination complete its overall aesthetic appeal but also aid towards there survival within captivity alongside other species living near by.

This adds yet another advantage when considering keeping one (or several) of these small decorative invertebrates at home – apart from being full aquatic organisms. They offer aesthetical value whilst swimming peacefully about your own personal mini habitant.

Average Size

Enthusiasts of aquarium hobby typically opt for heavily planted tanks since they create a natural atmosphere which allows small aquatic creatures to coexist harmoniously. Thai Micro Crabs, whose average size is only 0.4 inches (1 centimeter). Female Thai Micro Crabs are larger than the males. They are perfectly suitable inhabitants as they can easily explore the tank’s dense vegetation and look for ideal places to hide out in given its modest measurements. Due to their small size, it’s best not to handle them with a net as it’s easy to tear their limbs off. Be very careful when handling these tiny creatures!


To ensure they live a long and healthy life, Thai Micro Crabs require attentive care in an environment that stays the same. This kind of species has an average lifespan of one to 1.5 years when given what it needs to maximize its health.

Caring For Your Thai Micro Crab

For the health of your Thai Micro Crab, it is important to provide a suitable environment and adequate care. This requires having stable water conditions with appropriate parameters as well as an aquarium that has natural decorations for hiding spots. Their diet should be varied enough to meet their needs.

Regular maintenance is also essential in keeping them healthy, which involves monitoring temperature and pH levels, ensuring sufficient filtration and feeding, plus observing whether there are any signs of illness or stress, such as abnormal behavior or change in coloration. If so, then action must be taken promptly!

Aquarium Setup

In order to ensure Thai Micro Crabs are healthy and thriving, they require a tank of at least five gallons that is furnished with natural decorations like rocks and driftwood. This habitat should be realistically replicating their native environment. The presence of floating vegetation will provide extra hideaways for them as well as offer more stability regarding water quality levels.

In tanks larger than 20 gallons, they will get lost in the aquarium for the owner. You may never see them due to their small size. As such, we do not recommend them for aquariums larger than 20 gallons. Also keep in mind that these crabs are very small and can escape their tanks. Consider covering your tank and checking to see if you have any small cracks or holes covered.

It’s essential that prior to putting micro crabs into the aquarium, it has been properly cycled through its filter system first so everything remains stable when you finally introduce your new little friends, always making sure proper acclimation takes place during transfer! Drip accumulating is your friend with any invert. However, do not drip accumulate any livestock you purchase that was shipped to you.

Water Parameters

Keeping the water parameters in a suitable range for Thai Micro Crabs is important. This includes maintaining a neutral pH balance, with an ideal 6.5-7.5 range and hardness of 2-10 dGH as well as keeping the temperature between 70°F (24°C) – 80°F (28 °C). An accurate thermometer and pH test kit are essential to monitor these levels effectively so that your crabs remain healthy in their environment at all times.

Good filtration/oxygenation within the tank should also be provided regularly. It’s best suited for thai micro crabs if you install a small filter that helps remove debris while simultaneously adding oxygen into its habitat. Make sure to cover up any filter intakes by using some covering; otherwise, this might risk resulting in being sucked inside accidentally!


It is of utmost importance to perform consistent water changes and tests for Thai Micro Crabs, in order to ensure a safe environment. Water should be changed 10-20% every week as it helps sustain the quality and balance of the aquarium’s contents. Using an accurate thermometer and pH test kit will help you monitor temperature & PH levels accurately. As with most inverts they are sensitive to nitrate levels, so try to keep these under 40PPM.

Diet And Feeding Techniques

Providing your micro crabs with proper nutrition also plays an important role in keeping them healthy – they need a balanced diet that includes high-quality crab pellets, algae wafers along with small live or frozen foods such as brine shrimp/daphnia which can be offered multiple times throughout the day but feed only very tiny portions at each meal time.

Thai Micro Crabs are omnivorous scavengers that utilize their bristles to filter food particles from the water, such as microorganisms. As they get food by cleaning themselves with these small particles, they also like dining on pieces between floating plants. The best way to feed them is with dwarf shrimp food or powdered foods like shrimp baby given they have hairs on their legs that will capture food particles.

Shrimp Baby

This powdered food is perfect for baby shrimp

Buy On Amazon

The biggest challenge with these crabs is ensuring they get enough to eat. They are slow moving and any fish and even shrimp will outcompete them for food. The best advice is to feed them at night when all the fish are resting. Using a powered food and release it into the tank. The powder should be dusted over or near the crabs so they can get their food. They are also nocturnal and will be active during this time.

Behavior And Social Interaction

Thai Micro Crabs are known for their mellow nature and often take refuge in foliage or decorations within the tank. They won’t cause any harm to other inhabitants of a community tank as they tend not to be hostile towards others who share the space with them. It is advised to make sure there are ample hiding spots made up of various plants when these creatures go through molting periods since this can leave them exposed during those times.

Studying Thai Micro Crab behavior can be quite intriguing. It should also come as no surprise if you notice moments where they spend time idle or out of sight. Given its tendency to be very timid and shy, naturally, such occurrences will undoubtedly occur now and then anyway!

I know some hobbyists who keep them get frustrated that they never see them due to their reclusive nature. They are nocturnal and are best seen at night. They are best seen at night with a blue RBG light or under moonlights.


Breeding Thai Micro Crabs is a tricky task with high mortality rates, and it can be difficult to differentiate males from females due to their tiny size. Female Thai Micros lay eggs, which hatch into larvae. Most of these don’t survive due to their fragile size, making it hard to be successful.

This could potentially come down to parasites attacking the young crabs or an inadequate nourishment environment for them. Keeping natural environments suitable for proper growth may help ensure better breeding success among the micro crab population. If you are curious to learn how to master breeding them, there is one YouTuber who has documented this – her name is Rachel O’Leary, and I would recommend looking her up to learn more.

Male Vs Female Crabs


To distinguish between males and females of the Thai Micro Crab species, one can carefully inspect their lower body with a magnifying glass. Females typically have wider flaps than that of the male crabs. Size disparities are not hugely apparent. Close examination is necessary in order to identify the gender for these micro crustaceans. However, it is very difficult to sex these crabs due to their size. It’s easy to tear their limbs while handling them, and they can escape when examined.

Potential Health Issues

When it comes to Thai Micro Crabs, their health depends on having a stable environment and being monitored for health. Poor water quality, overcrowding in the tank, and injuries can all be sources of stress that contribute to bacterial and fungal infections. To maintain a healthy habitat for these crabs, watch out any signs such as weak coloring or loss of appetite due to behavior alterations.

Regular maintenance with a focus on monitoring parameters related to water levels is important so they stay comfortable within the established boundaries. This way, you ensure your micro crabs are safe from potential infection derived from too much pressure under which they may suffer inside an incorrect ambiance.

Choosing Compatible Tank Mates

When it comes to setting up a peaceful and comfortable living space for Thai Micro Crabs, choosing compatible tank mates is essential. Being quite mild-mannered and timid animals, these micro crabs require peaceful neighbors who won’t hassle or prey upon them.

Good Tankmates

Fire Red Cherry Shrimp

When deciding on good tank mates for your Thai Micro Crabs, it’s important to consider these creatures’ size and temperament. Consider these animals as possible tankmates:

Note that the vast majority of fish will be inappropriate for these crabs. Even small fish with small mouths will be curious about them and may nip. While they won’t eat the fish, the nipping is enough stress to make them fall ill or die from the stress.

For other inverts like dwarf shrimp – food competition is a problem. Shrimp are faster, more active, and faster to eat. Feeding your crabs at night would be best when the shrimp are less active in the tank.

Bad Tankmates

When you pick out their tank mates, be mindful of any potential competition for food or territory between the other fish and your Thai Micro Crabs. Keep in mind that larger fish can harass them, such as betta fish and certain crab species—which should Ideally be avoided so these delicate micro crabs remain stress-free. Here is another list of obvious bad picks:

The best tankmate at the end of the day is another Thai micro crab. If you want to go species only, consider building a colony of 25-30 and keeping them in one tank with lots of vegetation.

Other Species To Check Out

Not sure if this crab is for you? Check out our other crab guides below:

Purchasing Them

These crabs are imported, which makes success with transportation tricky. I would consider purchasing from a trusted online retailer like Flip Aquatics if you can’t find them at local pet stores. They spend the time to quarantine the animals and ensure they are in good shape and ready to transfer. Check out the link below to purchase them.

Frequently Asked Questions

How big do Thai micro crabs get?

Thai Micro Crabs typically reach a maximum size of 1/2 inch in diameter, making them perfect for small tanks.They may be shy when first introduced, but with time, they will happily cling to plants and perch atop driftwood.

Are Thai micro crabs hard to keep?

Thai micro crabs are a hassle-free species, flexible to different temperatures and undemanding about water parameters. Making them easy to care for. If anything what makes them harder to keep is they don’t compete for food well and may get eaten by tankmates.

What are the mini crabs in Thailand?

These aquatic creatures, scientifically known as Limnopilos naiyanetr, are commonly referred to as Thai Micro Crabs or “false spider crabs.” Found only in a single river in Thailand, these micro crabs can’t be seen anywhere else.

Can Thai micro crabs live with shrimp?

The popularity of Thai micro crabs amongst shrimp keepers is on the rise. Their peaceful demeanour and need for similar conditions make them perfect companions to dwarf shrimps in your aquarium. The ‘Thai Micro’ crab has all these features, making it a great choice for those wanting an aquatic partner with their crustaceans. The main issue with both species is food competition as shrimp will easily outcompete them. They should be feed separately to combat this.

What size tank is suitable for Thai Micro Crabs?

For a Thai Micro Crab, it is advisable to have a tank with at least 5 gallons of volume. This offers enough room for the crab to move around and enjoy its surroundings while exploring the tank’s decorations. The size also ensures that additional items can be added to keep things stimulating for your micro crab companion such as aquatic plants.

Closing Thoughts

To sum up, Thai Micro Crabs are quite extraordinary and can be a wonderful addition to an aquarium when given the right environment, care requirements, and compatible tank mates. If you take your time monitoring their behaviors, checking for health issues as well as maintaining their living space. They will certainly have increased chances of leading long lives in excellent condition.

These captivating creatures not only possess mesmerizing looks but also maintain a peaceful nature while exhibiting fascinating behavior, which all make them so very attractive to aquarists! So why don’t you considering adding these delightful micro crabs into your aquatic world and discover what lies within?

Leave a Comment


9 Types Of Geophagus (With Pictures)
Cichlids are some of the most popular freshwater fish families in the aquarium trade, famous for their bold markings and colors, interesting behavior, and vibrant personalities. While many species have a reputation for aggression, one group of cichlids, the 'earth eaters' are known for their relatively peaceful temperament and amazing colors.
The 7 Best Plants For Cichlid Tank (That They Won't Eat)
Cichlids are aggressive towards each other, but are they aggressive to live plants? Most Central and South American cichlids can be kept with a variety of aquarium plants, but African species are more challenging to pair due to water parameters. It's not impossible though!
Why Angelfish And Guppies Are A Deadly Combo
You might think that guppies are easy fish that can be kept with nearly any other species, right? While these small, hardy fish can get along with most fish species, they are not compatible with angelfish. Keep in mind that angelfish are a type of cichlid, and so they should be treated as such.