The Australian blenny (''Ecsenius australianus'') is a small marine blennioid fish of the genus ''

Ecsenius ''Ecsenius'' is a large genus of fish in the family Blenniidae. Several species, including ''Ecsenius midas'', the Midas blenny, and ''Ecsenius bicolor'', the bicolor blenny, are commonly sold at aquarium stores as pets. Species There are curren ...

''. They are small and reddish brown with a white ventral side. Australian blennies inhabit the shallow marine waters of the tropics. They are often found along the

Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system, composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...

and

Coral Sea The Coral Sea () is a marginal sea of the Pacific Ocean, South Pacific off the northeast coast of Australia, and classified as an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion. The Coral Sea extends down t ...

of Australia.

Taxonomy

This species is believed to be most closely related to '' E. fourmanoiri''. Similarities between these two species include "broad, darkly dusky bands and stripes" and "dark opercular margin , which are not found in other members of the "Opsifrontalis Group". Preserved specimens also bear similarity to '' E. opsifrontalis''. However, ''E. australianus'' differ from ''E. opsifrontalis'' and ''E. fourmanoiri'' by their number of fins rays and vertebrae.

Description

Australian blennies are small fish, reaching lengths of only . The dorsal two-thirds of the body is reddish-brown, with white spots forming two rows. The ventral third is white in colour. A reddish-brown stripe with white edges passes from the rear end of the operculum (gill covering) through the eyes. The colour of the stripes can vary by specimen, between bright orange-red and pinkish brown. Towards the posterior end, colouration turns grey. The

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

has twelve spines and 13–15 soft rays. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has two spines and 15–17 soft rays. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

usually has 13 soft rays but can occasionally have 14. The tail (caudal) fin possesses 14 rays. Australian blennies are

oviparous Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...

and lay eggs. The eggs develop at the bottom of the body of water and are adhesive.

Distribution and habitat

Australian blennies are distributed in the western Pacific Ocean, occurring in the

and

. They are associated with

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s and occur in shallow waters along the northern

of Australia. Whilst they are currently restricted to the northern Great Barrier Reef region, their range may expand southwards with those of several other similarly distributed species as temperatures increase due to

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

References

{{Taxonbar, from=Q781958 Australian blenny Marine fish of Eastern Australia Far North Queensland Taxa named by Victor G. Springer Australian blenny