A small, charming crab that lives among the tentacles of host anemones much like a clownfish, sweeping the water for food with feathery, fan-like mouthparts. Reef-safe and peaceful, it is kept for its looks and behavior rather than as nuisance-algae crew: it is a FILTER FEEDER of plankton and suspended detritus, not a grazer, so it doesn't control algae and needs a fed, plankton-rich tank to thrive.
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Educational only. KinStation content is reviewed by licensed veterinarians but cannot replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.
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Small: carapace to about 1.5-2.5 cm (0.6-1 in) wide, with feathery feeding mouthparts.
Lifespan
2–4 years
Social needs
pair
Native region
Tropical Indo-Pacific
Origin
Old World
Climate
🌴 Tropical
Water type
🌊 Marine
Family
Porcellanidae
Genus
Neopetrolisthes
Part of the Marine Crabs
Reef-dwelling crabs kept mostly as algae-grazing and scavenging cleanup crew. Many are useful and largely reef-safe when well fed, but most are opportunistic and can turn on snails, corals, or small fish if hungry — so stock conservatively and watch behavior.
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Larva
Most marine invertebrates hatch into microscopic planktonic larvae (such as the zoea of crustaceans or the bipinnaria/veliger of echinoderms and mollusks) that drift and feed in the water column. The larva looks nothing like the adult and undergoes major reorganization.
Photo coming soon
Juvenile
After settling out of the plankton, the juvenile takes on a recognizable miniature of the adult body plan — a tiny shell, a small star, or a translucent shrimp. Crustaceans grow by molting, shedding the exoskeleton to enlarge.
Photo coming soon
Adult
Adults reach full size and reproductive maturity with the species' mature shell, shape, or coloration. Many continue to molt or grow throughout life, and some show sex differences in size or claw/appendage shape.
Color & pattern variants
Natural variants occur in the wild; selectively bred (man-made) variants were developed in captivity.
Natural
Spotted (typical)
The usual form: a translucent cream-to-white body and claws speckled with red, brown or maroon spots, with feathery feeding fans on the mouthparts. A natural species, not a bred strain.
Habitat & enclosure
Keep one or a bonded pair in an established reef tank of 20-30 gallons (75-115 L) or more, ideally with a host anemone (such as a carpet, bubble-tip or similar) or at least sheltered live rock. Maintain stable tropical reef parameters: temperature 72-80F (22-27C), pH 8.1-8.4, salinity SG 1.024-1.026, alkalinity 8-11 dKH and low nitrate with zero ammonia/nitrite.
Neopetrolisthes maculatus is a tropical Indo-Pacific species that lives symbiotically within the stinging tentacles of large anemones, usually a single pair per anemone, gaining protection from predators. Moderate flow that delivers suspended food is beneficial; any reef lighting is fine (lighting is for the host anemone, not the crab).
Substrate
Substrate is unimportant to this crab; what matters is a host anemone or sheltered, current-swept perch and food in the water. Any reef sand or bare-bottom base is fine. Provide live rock structure near flow so it has a feeding station even without an anemone.
Equipment & setup
Standard reef equipment suffices: live-rock biofiltration, a heater, a protein skimmer and moderate flow on a copper-free system, with trace iodine maintained for molts. Because it filter-feeds, avoid stripping the water totally bare of plankton — heavy skimming plus zero feeding can starve it; target-feed suspended foods instead.
Diet
A filter (suspension) feeder, NOT an algae grazer: it unfurls long, feathery setae on its mouthparts to comb plankton, suspended detritus and other fine organic particles from the water column, sweeping them to its mouth. This is the key stocking fact — it will not clean nuisance algae. In the aquarium it needs a well-fed, plankton-rich system; supplement with broadcast foods such as live or frozen baby brine, rotifers, phytoplankton and finely powdered foods, or it will slowly starve in a sparse tank.
Behavior & temperament
Peaceful, reef-safe and shy, spending most of its time perched in or beside its host anemone, fanning for food, and darting back among the tentacles when startled. Its enlarged claws are for defense and squabbles, not hunting. It is best kept as a single specimen or a bonded male-female pair per anemone; rival pairs may fight over a host. Like other porcelain crabs it can shed a limb (autotomy) when stressed, regrowing it over later molts. Harmless to corals and fish.
Health
As a crustacean it is sensitive to copper (never use copper medications), to salinity and temperature swings, and to low iodine/trace elements that cause failed molts; maintain trace iodine and stable parameters and drip-acclimate very gently, as it ships and acclimates more delicately than hardy cleanup hermits. The two main husbandry pitfalls are starvation in a clean, under-fed tank (it needs suspended food) and stress from lacking a host or being harassed. Dropped limbs from stress usually regrow at the next molts. Avoid prolonged air exposure. (Educational only, not a substitute for advice from an aquatic veterinarian.)
Tips, DIY & hacks
Buy it as a peaceful, fascinating display invert and anemone companion, not as algae cleanup — it filter-feeds and won't touch nuisance algae. Provide a host anemone or a sheltered, current-swept perch, target-feed plankton-type foods, keep the tank copper-free, and acclimate it gently. A single crab or a bonded pair per anemone works best.
Reviewed and signed off by: KinStation Editorial — pre-launch draft (pending DVM review) on 2026-06-10