Thai Micro Crab
Limnopilos naiyanetri
Min Tank Size
10L
Adult Size
1 cm
Lifespan
1 year
School Size
3+
About
Found only in a single river system in Thailand, Limnopilos naiyanetri is about as niche as freshwater inverts get. Maxing out at roughly 1 cm across, these crabs are fully aquatic, which sets them apart from most crabs sold in the hobby that sneak out of tanks or drown if they can't access air. Their claws are covered in fine feathery setae, which they fan through the water column to catch suspended particles, biofilm, and microscopic organisms. They look almost spider-like in person, with long slender legs and a tiny carapace. Colors tend toward pale tan or grayish with subtle mottling.
Water conditions should stay soft to moderately hard with a slightly acidic to neutral pH. Temperature can range between 22 and 28 Celsius, though stability matters more than hitting any specific number. Because they rely on filter feeding and grazing on biofilm, a mature, well-established tank is non-negotiable. Bare, sterile tanks will starve them out fast.
A heavily planted nano setup full of java moss, leaf litter, and driftwood gives them both foraging opportunities and the cover they desperately need. Diet supplementation with liquid invertebrate foods, powdered fry food, and occasional micro-sized frozen foods helps fill the gap in smaller tanks where natural microfauna might not be abundant enough on its own.
These crabs are not for hobbyists who want something they can watch easily. They hide constantly, especially in well-lit tanks. If you want a unique invertebrate project and have the patience for a species that rewards careful observation over flashy displays, browsing community builds featuring Thai Micro Crabs will show you just how rewarding a proper setup can be.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Thai Micro Crab together
Best kept in a species-only nano tank; too fragile and small for safe cohabitation with most other animals.
Compatibility
These crabs should not be kept with fish. Even small nano fish like ember tetras or microdevario species may pick at them, stress them, or outcompete them for food. Their ideal companions are other tiny, non-predatory invertebrates such as small Neocaridina or Caridina shrimp, nerite snails, and ramshorn snails. Even then, shrimp that are considerably larger may accidentally bully them during molting. A species-only setup in a 10 to 20 liter tank is the most reliable approach. Planaria, hydra, or any predatory flatworm will also pose a genuine threat, so a clean, pest-free tank is important before adding them.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The biggest mistake people make is adding these crabs to a new or immature tank. Without established biofilm and microfauna, they slowly starve even if you're actively feeding. A tank running for at least three to four months before introduction makes a real difference. They also need near-perfect water quality since they're sensitive to ammonia spikes and temperature swings. Molting is a vulnerable period, and inadequate mineral content in the water can cause failed molts. Supplement with calcium sources if your water is very soft. Flow should be gentle enough that they can perch comfortably without being swept around.
Behavior & Aggression
Thai Micro Crabs show no meaningful aggression toward anything. They're simply too small and too timid to pose any threat to other inhabitants. They don't pinch or pursue tankmates, and conspecific interactions are largely indifferent. The real concern runs the other direction entirely. They are incredibly vulnerable to stress from larger or more boisterous animals, and even a curious snail bumbling into their hiding spot can send them into hiding for days. Aggression is a non-issue with this species. Vulnerability is the word to keep in mind.
Things to Know
- Extremely secretive, you may rarely see them without dense cover
- Short lifespan, often under 2 years even with perfect care
- Will be eaten or outcompeted by almost any fish, keep species-only or with tiny inverts
- Filter feeding means they need microfauna and fine particulates, not just pellets
- Extremely shy, best in a species only setup.
Community Sightings
No builds featuring this species yet.
Be the first to feature Thai Micro Crab in your build →Discover Tanks
Explore more builds from the community.
Explore More Species
More species to discover.
