Orange-banded hermit crab

Geographical Origin and Habitat: Trizopagurus strigatus is widely distributed across the tropical Indo-Pacific, ranging from the eastern coasts of Africa and the Red Sea to Hawaii and French Polynesia. It inhabits shallow coral reefs, sandy lagoons, and rocky intertidal zones to depths of about 25 meters. This species has adapted to live in gastropod shells with narrow, slit-like openings, such as those of cone snails (Conidae).

Taxonomy: Belongs to the class Malacostraca, order Decapoda, and family Diogenidae. Described by Herbst in 1804, this species features a remarkably flattened dorso-ventral body shape. This unique evolutionary adaptation allows it to inhabit cone and mitre shells that are inaccessible to other hermit crabs with rounder bodies.

Social Behavior: A very peaceful marine invertebrate that is active both day and night. It spends its time crawling over live rock and substrate searching for food. Unlike more aggressive hermit crabs, it displays low aggression toward tankmates and rarely attacks live snails for their shells, unless there is a severe shortage of suitable empty shells.

Coloration and Sexual Dimorphism: Features spectacular coloration, with legs and claws of a brilliant reddish-orange decorated with distinct white or pale yellow transverse bands. The soft abdomen is protected inside its shell. No visible external sexual dimorphism exists; sexing is based on gonopore position on the underside, which is invisible in live specimens.

Tank Setup: Requires a marine aquarium of at least 80-100 liters with plenty of live rock. It is essential to provide a variety of empty gastropod shells on the sandy substrate, prioritizing narrow, cone-shaped shells (like Conus or Strombus shells) of different sizes to facilitate growth and molting. Ensure rockwork is stable.

Diet and Feeding: An opportunistic omnivore and excellent scavenger. It feeds on filamentous green algae, detritus, fish food leftovers, and benthic micro-organisms. In the aquarium, it readily accepts sinking pellets, flakes, and small pieces of fresh seafood. It helps keep the aquarium clean by consuming decaying matter.

Water Quality: Maintaining stable water parameters is necessary for its long-term health. Temperature between 24°C and 28°C, pH between 8.1 and 8.4, specific gravity of 1.023 to 1.025, and dKH between 8 and 12. Ammonia and nitrite must remain at zero. Adequate levels of calcium, magnesium, and especially iodine are required for molting.

Compatibility and Tankmates: Coexists peacefully with small-to-medium reef fish and corals. Avoid shell-crushing predators such as triggerfish, puffers, and large wrasses. It can be housed with other herbivorous snails and hermit crabs, provided there is enough food and an excess of empty shells to prevent competition.

Aquarium Breeding: Breeding in home aquaria is extremely difficult. Fertilized females carry eggs under their soft abdomen inside the shell. The hatched larvae are planctonic and undergo several developmental stages that require specialized micro-foods, and they are typically removed by standard aquarium filters.

Risks and Diseases: The primary risk is molting failure due to poor water quality or iodine deficiency. During molting, the crab will hide and should not be disturbed. Highly sensitive to copper treatments; copper-based medications must never be used in a display tank housing this hermit crab.