Halloween Hermit Crab
Halloween Hermit Crab

Halloween Hermit Crab

Ciliopagurus strigatus
SynonymsPagurus annulipes, Trizopagurus strigatus
Maximum Size5cm (2”)
Sexual DimorphismUnknown
TemperatureTropical: 22-28 deg C (72-82deg F)
Water ParametersSG: 1.020-1.025, pH: 8.1-8.4
CompatibilityReef with caution
LightingNo special requirements
Reef Aquarium CompatibilityUsually safe when kept in relatively low numbers. Will not eat corals, but may damage them whilst lumbering about in their ongoing search for food. Do not keep with ornamental snails.


The Halloween Hermit Crab, with its vibrant orange and red striped ‘stockings’, is an eye-catching addition to the marine aquarium. This semi-aggressive species is an excellent scavenger, eating any uneaten food and detritus that it may come across, as well as consuming many different types of green algae. Having said that, they must, of course, be offered a varied diet and not allowed to solely survive on scraps, but they do make for excellent clean-up crew. Provide a mature aquarium with a good amount of live rock (with some algae) which they will enjoy browsing upon, and a few open areas of sandy substrate which they will appreciate sifting through, in turn keeping the substrate nicely turned over. This is a fairly small hermit crab, attaining a maximum size of around 5cm/2” not including the shell, which it occupies to afford itself protection from predators. It is important to always have a supply of empty shells on hand, ideally slightly larger than the one that the crab is currently occupying, to enable it to move to larger quarters as it grows. Without ample choices of larger homes, these crabs have been known to attack and kill other hermits in order to steal their shell, so always have plenty on offer to prevent such incidents from occurring. Halloween Hermit Crabs have been successfully kept in reef aquaria, but a few words of caution are required. Whilst they do not actively feed on sessile invertebrates, they will think nothing of trampling over certain flattish corals in their quest to find food items; likewise, they will try and take food from the clutches of corals that take larger items, such as sun corals, with much tenacity and enthusiasm. So careful observation is the key, placing any particularly delicate or vulnerable corals in suitable areas that may be more awkward for the crabs to reach, and thus keeping them safe from unwanted trampling whilst searching for food items. This species spends a good part of the day hidden in crevices amongst the live rock, particularly newly introduced specimens, venturing out during the evening time to look for food; their comical antics being well observed under blue moon lighting. As the crabs get used to their environment and gain confidence, they may start to spend more time out in the open during the hours of daylight, especially if they get used to foods being offered at certain times. Do not keep alongside any other species of hermit crab, as they will fight. Avoid any small, docile bottom-dwelling fish, such as dragonets, firefish, and some gobies, as they are likely to be predated on at night when the crabs are at their most active. Likewise, do not keep in tanks with large predators, such as triggers or puffers. Copper treatments are best avoided, as even the tiniest amounts can be lethal.


An omnivorous species, which must receive both green and meaty foods. Scavenges on most aquarium fare such as Mysis shrimp, vitamin-enriched brineshrimp, krill, chopped prawns/mussel meat etc., along with seaweed and many types of algae (including hair algae and Cyanobacteria). If algae becomes depleted in the aquarium, ensure you offer these crabs plenty of other choices of greenfoods on a regular basis.



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