Scarlet Reef Hermit Crab Starter Care Guide
A practical introduction to scarlet reef hermit crab care, including health risks, water quality, tank setup, food and behaviour.
Use this guide to notice and organize information. Contact a qualified veterinarian for medical concerns or urgent change.
About the Scarlet Reef Hermit Crab
Scarlet reef hermit crabs are small red-legged scavengers that carry an empty snail shell as protection. As they grow, they need a choice of larger shells rather than a single replacement.
They graze algae and leftovers, but they cannot clean an aquarium faster than excess light, nutrients or overfeeding creates waste.
Health risks to know about
Important concerns include copper exposure, ammonia or nitrite poisoning, failed moults, starvation, unsuitable shells and injuries from fighting or predatory tank mates.
Repeatedly leaving the shell, loss of coordination, an incomplete moult, damaged limbs or unusual inactivity needs prompt water testing and a husbandry review.
Tank, water and equipment
Use a mature, fully cycled marine aquarium with stable rockwork, grazing surfaces, hiding places and several clean unpainted spare shells in suitable shapes and sizes.
Measure salinity with a calibrated refractometer. A specific gravity around 1.023 to 1.026 is a common invertebrate range, with ammonia and nitrite kept at zero.
Food and feeding
Offer small portions of complete marine omnivore food and marine algae when natural grazing is limited.
A hungry hermit is more likely to harass snails, so do not rely on scraps alone.
Behaviour, tank mates and enrichment
Climbing, shell inspection and hiding during a moult are normal. Leave a range of spare shells available as the crab grows.
Scarlet reef hermits are often reef compatible, but any hermit may disturb loose coral frags or attack a snail for food or its shell.
When to contact an aquatic veterinarian
Get help for gasping, collapse, severe wounds, major swelling, inability to stay upright, rapid unexplained deaths or a problem that continues after water parameters are corrected.
Test ammonia, nitrite, nitrate, pH, temperature and salinity whenever behaviour changes. Water quality is part of the medical history, so record results before contacting an aquatic veterinarian.
Read the supporting material
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Supports the species-specific care summary for Scarlet Reef Hermit Crab.
Original source ↗02professional org · Ornamental Aquatic Trade AssociationHow to Test for Water Quality in a Marine Tank / AquariumSupports the aquarium cycling and water-quality context used in this guide.
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