Variable triplefin

Taxobox | name = Variable triplefin
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Perciformes
familia = Tripterygiidae
genus = "Forsterygion"
species = "F. varium"
binomial = "Forsterygion varium"
binomial_authority = (Forster, 1801)

The variable triplefin or striped triplefin, "Forsterygion varium", is a triplefin of the genus "Forsterygion", found in Australia including Tasmania and all around New Zealand in rock pools and depths down to 30 metres, in reef areas of broken rock with kelp.

The variable triplefin is one of the largest of the triplefins, reaching 20 centimetres at the south of the South Island but about 12 centimetres elsewhere, and also one of the commonest at many localities. It is similar to the Scaly-Headed Triplefin but lacks the rough bony armour covering on the head, which is flattened.

Its colouring is a mottled red-fawn often with a greenish tinge, with a series of about 6 dark red or red-black irregular vertical bars on the top half of the body.

The breeding season lasts from May to October. During this the male turns an almost uniform grey-black with blue margins on the first and second dorsal fins. Both sexes defend territories all year. The young settle out of the plankton between September and December when they are 15 to 20 millimetres long, and often take cover within the spines of sea urchins where they are relatively safe.

The variable triplefin's diet consists of small crabs and amphipods and other invertebrates. Their lifespan is between 3 and 4 years.

References

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*Tony Ayling & Geoffrey Cox, "Collins Guide to the Sea Fishes of New Zealand", (William Collins Publishers Ltd, Auckland, New Zealand 1982) ISBN 978-0-00-216987-5