--- title: Kosugei Hermit Crab (Catapagurus kosugei) scientific_name: Catapagurus kosugei common_name: Kosugei Hermit Crab taxon: Hermit crabs published: 2025-09-24T12:39:11.310Z updated: 2026-08-15T16:49:01.818Z tags: Kosugei Hermit Crab, Catapagurus kosugei, Hermit crabs, Red Sea, Marine Life, Diving url: https://redseacreatures.com/taxon/invertebrate/crustaceans/hermit-crabs/kosugei-hermit-crab --- # Kosugei Hermit Crab (*Catapagurus kosugei*) ## Quick facts - **Group:** Hermit crabs (*Paguroidea*) - **Size:** up to 3 cm - **Depth:** 5-50 m - **Diet:** Detritivore - **Activity:** Nocturnal - **Rarity:** Rare - **Habitat:** Sand and silty bottom away from reef - **Reproduction:** Egg layer, Gonochoric ## How to recognise it - pale slender hermit crab with a very long right claw in males - in small light shells on open sand - long thin walking legs, adapted to soft bottom - length up to 3 cm A pale, long-legged hermit crab of open sand, with a right claw in males that is stretched out of all proportion to the rest of the animal. Soft bottom is a different problem from reef. There is no rubble to hide in, shells are scarcer because fewer snails die there, and everything is exposed - so the hermit crabs that live on sand are slighter, paler and faster than the reef species, and they carry the lightest shell that will do rather than the strongest. The elongated claw in males is a signal used in disputes and courtship, held out and waved rather than used to fight, which is common in animals where the alternative is an expensive brawl on open ground. It works the sand at night for detritus and buries itself by day. Divers cross these flats and see nothing, because a three-centimeter animal in a small shell is indistinguishable from the debris around it. ## Also known as - **Japanese:** コスゲエビスヤドカリ ## Scientific synonyms - *Hemipagurus kosugei* Asakura, 2001 --- *Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/crustaceans/hermit-crabs/kosugei-hermit-crab)* *Updated: August 15, 2026*