Blue Leg Hermit Crab

The Blue Leg Hermit Crabs also known as Tricolor Hermits or Dwarf Blue Legs are tiny powerhouses and used extensively in the marine aquarium hobby for control of nuisance algae including hair algae, diatoms and cyanobacteria. Blue Legs congregate in large numbers in the wild feeding upon many types of algae and do a wonderful job within a reef tank consuming algae as well as leftovers. Size per individual is roughly 1/2″ – 1″ inch shell.

Introduction to Blue Legged Hermit Crab (Algae Eater & Cleanup Crew Essential)

The blue legged hermit crab (Clibanarius tricolor) is a small but effective member of the aquarium cleanup crew, known for grazing on nuisance algae, detritus, and leftover food. Found in shallow reefs and seagrass beds, these crabs are highly adaptable and play a crucial role in keeping aquariums clean. With their bright blue legs and small size, these hermit crabs are an excellent choice for nano tanks and large reef systems alike.

Care Requirements

Care Level: Easy – Low-maintenance and beginner-friendly Minimum Tank Size: 10+ gallons Aquarium Setup: Requires rockwork, sand, and spare shells for growth Blue legged hermits spend most of their time foraging and are constantly in motion, helping to break down organic waste.

Diet & Nutrition

Blue legged hermit crabs are omnivorous scavengers, meaning they require a mix of algae and meaty foods for a balanced diet. Diet: Omnivorous – Prefers algae, detritus, and leftover food Recommended Foods: Hair algae, diatoms, and film algae Uneaten fish food and organic waste Algae wafers and sinking pellets (if food is scarce) Supplementing their diet with seaweed or meaty foods helps maintain their coloration and longevity.

Lifespan & Growth Rate

Lifespan: 2-4 years Growth Rate: Slow – Typically reaches up to 1 inch As hermit crabs grow, they must molt and find larger shells to accommodate their size.

Temperament & Compatibility

Temperament: Peaceful to Semi-Aggressive – Can be territorial over shells Reef Safe? Yes – Safe for corals and fish but may target small snails for shells To prevent aggression, always provide a variety of empty shells to reduce competition among hermit crabs.

Common Challenges & Considerations

Shell Stealing: May attack snails or other hermits if not provided with empty shells. May Dislodge Corals: Can accidentally knock over frags or small corals while foraging. Opportunistic Scavenger: If underfed, may pick at soft tissue or weakened tankmates. Providing ample food sources and extra shells ensures a peaceful and effective cleanup crew.

Water Conditions

Temperature: 74-80°F dKH (Alkalinity): 8-12 pH: 8.1-8.4 Specific Gravity: 1.024-1.026 Stable water conditions support healthy molting and long-term survival.