Blue Maomao

Fascinating facts about the Blue Maomao

• A 2019 landing of 3,518 kilograms (7,756 lb) shows the blue maomao is commercially fished in New Zealand.
• When a school of blue maomao chases shrimp near the surface, they can cause the water to foam.
• Each adult carries a set of protrusible jaws with multiple rows of tiny teeth, perfect for snapping up larger zooplankton. This specialized mouth lets them switch to grazing algae when plankton runs low, showing an adaptable diet that buffers them against food shortages. Their flexibility illustrates how predators can become opportunistic feeders without losing efficiency.
• From September through November the species releases eggs 0.8 mm across with an oil droplet; juveniles are recorded from October to December.
• A single blue maomao can live up to 15 years, and each night it seeks a specific rock crevice to rest, changing its skin from deep blue to mottled dark green.

At a glance

About the Blue Maomao

The blue maomao (Scorpis violacea) cuts a striking figure in the surf-lined reefs of the southwestern Pacific. Its laterally compressed, deep body ends in a pronounced forked tail, while a palette of deep blue sweeps across its dorsal surface, fading to a pale ventral hue. At night the fish transforms, mottling into a dark green that blends with shadowed rock crevices. Juveniles wear a muted grey coat highlighted by a vivid yellow anal fin, and the species can reach a fork length of up to 45 cm (18 in). Its protrusible jaws, lined with rows of tiny, tightly packed teeth, are perfect for snapping up swarms of zooplankton, though the maomao will graze on algae when plankton runs thin. In the daylight, schools dart over rocky outcrops, sometimes frothing the water as they chase shrimps near the surface, a behavior that hints at their tactile nature, they often rub against pebbles and even visit cleaner fish without obvious need. Blue maomao are true inshore specialists, inhabiting waters from the surface down to 30 m (98 ft) around New Zealand’s North Island, the Kermadec Islands, and parts of Australia. They favor rocky habitats where each individual selects a favourite sleeping nook among the stones, changing colour to a mottled green as night falls. Occasionally they huddle over sheltered sandy patches, sleeping in groups. Reproduction runs from September to November, yielding 0.8 mm eggs with oil droplets; juveniles appear from October to December and can live up to 15 years, a lifespan that supports both commercial fisheries, 3,518 kg (7,756 lb) were landed in New Zealand in 2019, and a popular spearfishing target.

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