The olive rockfish (''Acanthoclinus fuscus'') is a

longfin The longfins, also known as roundheads or spiny basslets, are a family, Plesiopidae, which were formerly placed in the order Perciformes or considered indeterminate percomorphs, but are now considered basal blenniiforms. They are elongated fishe ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Plesiopidae The longfins, also known as roundheads or spiny basslets, are a Family (biology), family, Plesiopidae, which were formerly placed in the order Perciformes or considered indeterminate Percomorpha, percomorphs, but are now considered basal Blenniifo ...

. Found only in

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

's intertidal zone and in rock pools at low tide, the fish grow to a

length Length is a measure of distance. In the International System of Quantities, length is a quantity with Dimension (physical quantity), dimension distance. In most systems of measurement a Base unit (measurement), base unit for length is chosen, ...

of up to . They are permanent inhabitants of the intertidal zone, which demonstrate homing behaviour, and are found in pools among rocks or boulders. If the conditions in these pools become unsuitable they may leave the pools. Their diet consists mostly of invertebrates, mainly

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s and

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s. They are able to breathe air. This species swims with a sinuous motion similar to an eel. The male guards the eggs. Olive rockfish are black with a distinctive white band on the head. They can be found in Moncks Bay in Christchurch New Zealand at High tide in winter months as well.

References

Olive rockfish Endemic marine fish of New Zealand Fish described in 1842 {{Plesiopidae-stub