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    Hermit crab

    Large hermits

    Dardanus, Aniculus, Trizopagurus spp.

    Avoid in most reef tanks

    Group
    Hermit crab
    Care level
    Intermediate
    With corals
    Not reef safe

    What does the large hermits do in a reef tank?

    Anything, including tankmates

    With corals: No

    How many should you keep?

    Species-only tanks

    One US gallon is 3.785 litres and one UK gallon is 4.546 litres, so a "per gallon" rule depends on whose gallon it means.

    What can go wrong?

    Dislodge rock and corals and attack tankmates

    Which tankmates are risky?

    Fish

    Fish that may eat or harass it.

    None of the fish in this guide is known to eat or harass it.

    Other invertebrates

    Invertebrates it may harm, or that may harm it.

    Take care (7)

    • Trochus snailLarge hermitss kill snails to take their shells; give spare empty shells.
    • Turbo snailLarge hermitss kill snails to take their shells; give spare empty shells.
    • Astraea (Astrea) snailLarge hermitss kill snails to take their shells; give spare empty shells.
    • Cerith snailLarge hermitss kill snails to take their shells; give spare empty shells.
    • Nassarius snailLarge hermitss kill snails to take their shells; give spare empty shells.
    • Nerite snailLarge hermitss kill snails to take their shells; give spare empty shells.
    • Fighting conchLarge hermitss kill snails to take their shells; give spare empty shells.

    These checks follow the reasons fish and invertebrates clash: same species or genus, similar shape, mouth size, temperament, food, burrows, tank size and the order they are added. Individual animals differ; every source agrees on that.

    Sources

    1. Practical Fishkeeping (UK), essential cleaners for the reef tank (date not shown)Read 21 October 2026, read in full.

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    Blue leg hermit crab

    Clibanarius tricolor

    Care
    Beginner
    Group
    Hermit crab
    Corals
    Reef safe with caution

    Photo RevolverOcelot, CC BY-SA 3.0

    Scarlet reef hermit

    Paguristes cadenati

    Care
    Beginner
    Group
    Hermit crab
    Corals
    Reef safe

    Photo Andreas März, CC BY 2.0