A striking large conch whose shell flares into long, claw-like finger projections — the 'spider' look — with females bearing longer, curved digitations than males. A peaceful Indo-Pacific algae and detritus grazer that plows sand and rock; it grows large and needs space, but is reef-safe and uses the same leaping clawed-foot locomotion and stalked eyes as its smaller relatives.
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Shell averages about 18 cm (7 in), up to 29 cm (11 in) including the long finger-like projections.
Lifespan
4–10 years
Social needs
solo
Native region
Indo-West Pacific (widespread on shallow reefs, lagoons and mangrove edges)
Origin
Old World
Climate
🌴 Tropical
Water type
🌊 Marine
Family
Strombidae
Genus
Lambis
Part of the Conchs
Large marine gastropods that plow and sift sand beds as living detritus and algae clean-up crew. Distinctive for their 'hopping' leaping foot, stalked eyes and heavy flared shells, most are peaceful sand-bed specialists — though a few relatives are predatory and not reef-safe.
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
Typical (clawed)
The standard form, with a heavy shell flaring into long claw-like marginal digitations and a glossy aperture; females show longer, dorsally curved fingers than males. A natural species, not a bred strain.
Habitat & enclosure
Give one a larger established reef or FOWLR tank — comfortably 55 gallons (210 L) or more — with a broad open fine sand bed plus live rock, since this is a sizeable conch that needs room to plow and graze. Maintain stable tropical reef parameters: temperature 72-82F (22-28C), pH 8.1-8.4, salinity SG 1.024-1.026, alkalinity 8-11 dKH and low nitrate.
It is widespread across the shallow Indo-West Pacific, on reef flats, sandy lagoons and mangrove-edge zones, where it grazes red and other algae. Any reef lighting and gentle-to-moderate flow are fine; provide sand area to match its size.
Substrate
A broad, fine sand bed of at least 1-2 inches (2.5-5 cm) plus live rock is essential — it plows sand and grazes rock to feed, so bare-bottom tanks are unsuitable. Allow generous open sand area for a large conch.
Equipment & setup
Standard marine gear suffices: live-rock biofiltration, a heater, a protein skimmer and gentle-to-moderate flow. No special lighting is needed; the priorities are tank size and sand-bed footprint to suit a large grazer.
Diet
A herbivorous grazer and detritivore that feeds on red algae, film and turf algae, diatoms and detritus across sand and rock. As with other conchs it can exhaust a clean tank's algae, so supplement with dried seaweed (nori) and algae wafers to prevent starvation; its larger size means a larger appetite.
Behavior & temperament
Peaceful and reef-safe toward fish, corals and inverts. Its long shell 'fingers' are defensive armor and a righting aid, not weapons against tankmates. It plows the sand and grazes rock, leaping on the strong clawed foot rather than gliding, with eyes on stalks. Its size and weight can dislodge loose frags or unstable rock, so secure the aquascape; keep one per tank.
Health
Sensitive to copper, salinity and temperature swings and air exposure like all marine snails — drip-acclimate slowly and never use copper meds. Starvation in under-fed, over-clean tanks is the main risk for a grazer this size; feed nori. A large conch flipped onto bare hardscape may struggle to right itself despite its leverage-giving spines, so check on it. Remove any dead snail promptly. (Educational only, not a substitute for advice from an aquatic veterinarian.)
Tips, DIY & hacks
Drip-acclimate over 1-2 hours and never expose it to air. Choose it for a larger tank with real sand and an algae standing crop, and supplement with nori so it doesn't starve. Secure rockwork and frags against its bulk, and admire the dramatic clawed shell — females show the longest, most curved fingers.
Reviewed and signed off by: KinStation Editorial — pre-launch draft (pending DVM review) on 2026-06-09