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Emerald Crab
Crab

Emerald Crab

Mithraculus sculptus

The reef trade's go-to for eating Valonia (bubble algae), but the "safe" reputation has a real asterisk — when underfed or crowded, it opportunistically picks at coral polyps, zoanthids, snails and even small shrimp. Feed it well and it stays a model tenant; starve it and it becomes a liability.

Temperament
Peaceful
Max size
1.6"
Min tank
20 gal
Reef-safe
Reef safe with caution
Diet
Omnivore
Zone
Rockwork, Caves
Keep just one per tank — two will fight.
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Tankmates

How Emerald Crab gets on with the rest of the reef, checked pair by pair by the same engine as the live pre-flight.

Best kept apart

A real clash — aggression, predation or a same-genus fight.

Leopard WrasseLeopard Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Melanurus WrasseMelanurus Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Yellow Coris WrasseYellow Coris Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Coral HawkfishCoral Hawkfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Red Coris WrasseRed Coris Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Christmas WrasseChristmas Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Antennata LionfishAntennata Lionfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Picasso TriggerfishPicasso Triggerfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Queen AngelfishQueen Angelfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Raccoon ButterflyfishRaccoon Butterflyfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Pearlscale ButterflyfishPearlscale Butterflyfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Ornate Leopard WrasseOrnate Leopard Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Dragon WrasseDragon Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Divided Leopard WrasseDivided Leopard Wrasse hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Valentini PufferValentini Puffer hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Volitans LionfishVolitans Lionfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Zebra Dwarf LionfishZebra Dwarf Lionfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Fuzzy Dwarf LionfishFuzzy Dwarf Lionfish hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Snowflake MoraySnowflake Moray hunts small cleanup-crew inverts — your Emerald Crab is on the menu.Zebra MorayZebra Moray hunts small cleanup-crew inverts — your Emerald Crab is on the menu.