Green Clown Goby (Gobiodon histrio)

The Green Clown Goby, also known as the Broad-barred Coral Goby, is a tiny, charismatic resident of the reef. Similar to the Citron Goby you asked about earlier, this species belongs to the genus Gobiodon and is a dedicated "coral dweller." It is prized for its intricate, "painted" appearance and its bold personality, often acting as the tiny "king" of its favorite coral colony.

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Key Information

• Common Names: Green Clown Goby, Broad-barred Coral Goby, Warpaint Goby

• Scientific Name: Gobiodon histrio

• Origin: Indo-Pacific (Red Sea to the Great Barrier Reef)

• Max Size: 3.5 cm (approx. 1.4 inches) — one of the smallest reef fish.

• Lifespan: 2–4 years

• Temperament: Peaceful; but territorial toward other Gobiodon

• Diet: Carnivore – Small meaty foods

• Care Level: Easy

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Appearance & Identification

The Green Clown Goby looks like it has been decorated with tribal "war paint":

• Base Color: A smooth, matte pale green to lime green.

• The Markings: Features several vertical red or pinkish-orange bars on the head and horizontal broken lines/spots across the body.

• Size: It is significantly smaller and more "squat" than the Citron Goby.

• Toxic Skin: Like its cousins, it produces a bitter, toxic mucus that makes it unpalatable to most predators.

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Behaviour & Tank Compatibility

• The Percher: Lacking a swim bladder, it spends its day "sitting" on coral branches or rock ledges. It uses its fused pelvic fins as a suction cup to stay anchored in high-flow areas.

• Coral Hosting: In the wild, they are almost always found within stony corals (SPS), specifically Acropora.

• Reef Safe (with Caution): While safe with most inhabitants, they may nip at the polyps of the coral they reside in to clear a spot for eggs. In a small tank with a single coral, this can be stressful; in a larger reef, the coral usually grows faster than the goby can nip.

• Social Structure: Keep singly or as a mated pair. They will aggressively chase away other clown gobies that try to sit on their specific coral "throne."

• Tank Mates: Excellent for nano and pico reefs. Safe with shrimp, snails, and peaceful fish. Avoid large, predatory fish that might ignore the "bad taste" and try to swallow them.

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Ideal Tank Setup

• Tank Size: Perfect for tiny systems; a minimum of 20L–40L (5–10 Gallons) is plenty.

• Rockwork & Corals: They are most happy when provided with branching SPS corals or "branchy" live rock. They love to wedge themselves deep into the branches where they feel secure.

• Flow: They handle moderate flow very well, as they are built to live in the high-energy surge zones of the reef crest.

• Feeding: They are "ambush" planktivores. They wait for food to drift by and then dart out to grab it. Feed 2 times daily with frozen cyclops, baby mysis, or oyster eggs.

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Why Choose the Green Clown Goby?

The Green Clown Goby is for the hobbyist who appreciates the small details. It is a "hidden gem" that you have to look closely to find, but once you spot it perching on a coral branch, its "warpaint" face and grumpy expression are incredibly endearing. It is a hardy, fascinating, and low-impact addition that brings a specialized bit of reef ecology into your home.