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    Avoid for beginners

    Copperband butterflyfish

    Chelmon rostratus

    Also sold as Beaked coralfish

    Not for beginners

    Copperband butterflyfish (Chelmon rostratus), photographed in the sea or an aquarium
    Photo: Luc Viatour, CC BY-SA 3.0, via Wikimedia Commons
    Care level
    Advanced
    Adult size
    20.3 cm in aquariums
    Minimum tank
    492 litres
    Temperament
    Peaceful
    With corals
    Reef safe with caution
    Captive-bred
    Wild-caught (captive-bred rare)
    IUCN status
    Least Concern
    Show volumes in

    How do you care for the copperband butterflyfish?

    Peaceful.

    Feeding

    Carnivore.

    Hard to start feeding; often bought to eat Aiptasia and then starves.

    Tank and special needs

    Plan for at least 492 litres of water (the care sheet says 130 US gallons).

    Mature tank.

    Corals and invertebrates

    Anemones (including Aiptasia), feather dusters, some LPS.

    Which tankmates suit the copperband butterflyfish?

    Alone; no other butterflyfish.

    Suggested order in a mixed tank: add after the first peaceful fish.

    More than one copperband butterflyfish

    Keep one copperband butterflyfish: two of the same species usually fight.

    Other fish

    Checked against the other 59 fish in this guide, assuming a tank big enough for both. Individual fish differ, so treat this as a starting point.

    Take care (3)

    • Maroon clownfishMaroon clownfish is aggressive and may bully the copperband butterflyfish, especially if the bully is added first.
    • Humbug damselHumbug damsel is aggressive and may bully the copperband butterflyfish, especially if the bully is added first.
    • Powder blue tangPowder blue tang is aggressive and may bully the copperband butterflyfish, especially if the bully is added first.
    Usually fine together (56)

    Invertebrates

    Only the invertebrates with a known risk are listed.

    Take care (2)

    • Tiger tail sea cucumberA stressed or dead tiger tail sea cucumber can release toxins that harm fish; cover pump intakes.
    • Sea appleA stressed or dead sea apple can release toxins that harm fish; cover pump intakes.

    Corals and anemones

    Only the corals and anemones with a known risk are listed.

    Take care (22)

    • Hammer coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Frogspawn coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Torch coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Duncan coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • AcanCopperband butterflyfish may nip LPS corals, more so when underfed.
    • FaviaCopperband butterflyfish may nip LPS corals, more so when underfed.
    • FavitesCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Chalice coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • BlastomussaCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Candy cane coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Bubble coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • GonioporaCopperband butterflyfish may nip LPS corals, more so when underfed.
    • AlveoporaCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Open brain coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • LoboCopperband butterflyfish may nip LPS corals, more so when underfed.
    • GalaxeaCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Scroll coralCopperband butterflyfish may nip LPS corals, more so when underfed.
    • Bubble tip anemoneCopperband butterflyfish may nip anemones, more so when underfed.
    • Rock flower anemoneCopperband butterflyfish may nip anemones, more so when underfed.
    • Mini maxiCopperband butterflyfish may nip anemones, more so when underfed.
    • Carpet anemones (Haddon's, giant)Copperband butterflyfish may nip anemones, more so when underfed.
    • Ritteri anemoneCopperband butterflyfish may nip anemones, more so when underfed.

    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.

    Quarantine and health

    Fragile; ich prone.

    New fish are the most common way disease gets into a reef tank. Quarantine every fish in a separate tank before it joins the display, and choose a method that suits its tolerance of copper.

    Captive-bred or wild?

    Wild-caught.

    What does it cost in the UK?

    about £55. This is one UK retailer’s listing on 21 October 2026, not a market average, and every item was sold out on that day.

    Sources

    1. LiveAquaria (US retailer) care sheetRead 21 October 2026, read in full. Used for: stats.
    2. FishBase species summaryRead 21 October 2026, read in full. Used for: max length.
    3. Kraken Corals (UK retailer) catalogueRead 21 October 2026, read in full. Used for: UK price.

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    Adult size
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    Tank from
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    Photo Diego Delso, CC BY-SA 4.0

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    Photo Diego Delso, CC BY-SA 4.0