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Family of fishes

Handfish are marine ray finned fishes belonging to the family Brachionichthyidae, a group which comprises five genera and 14 extant species and which is classified within the suborder Antennarioidei in the order Lophiiformes, the anglerfishes. These benthic marine fish are unusual in the way they propel themselves by walking on the sea floor rather than swimming.

The handfish were first proposed as a family, Brachionichthyidae, in 1878 by the American ichthyologist Theodore Gill. The Brachionichthyidae is classified within the suborder Antennarioidei within the order Lophiiformes, the anglerfishes. The Brachionichthyidae is regarded as the most basal family within the suborder Antennarioidei.

Handfish are found today in the coastal waters of southern and eastern Australia and around the island state of Tasmania. This is the most species rich of the few marine fish families endemic to the Australian region, with all but three species found there. There are 14 species of handfish around Tasmania.

The prehistoric species, Histionotophorus bassani, from the Lutetian of Monte Bolca, is now considered to be a handfish, sometimes even being included in the genus Brachionichthys. Considering the low extant diversity, restricted geographical distribution, and very meagre fossil record of antennarioids in general, the existence of fossil representatives of the family Brachionichthyidae is unusual.

In 1996, the spotted handfish (Brachionichthys hirsutus) was the first marine fish to be listed as critically endangered in the IUCN Red List. With its only habitat in the Derwent River estuary and surrounds, it is threatened by the Northern Pacific seastar's invasion into southern Australian waters. The Northern Pacific seastar (Asterias amurensis), preys on not only the fish eggs, but also on the sea squirts (ascidians) that help to form the substrate that the fish spawn on. The cause of the decline in spotted handfish is unclear. Suggested causes may include disturbance of benthic communities and predation on egg masses by the introduced northern Pacific seastar, habitat modification through increased siltation, heavy metal contamination or urban effluent. The lack of a pelagic larval stage and low rates of dispersal may be responsible for their restricted distributions and may also have an impact on handfishes ability to recolonise areas where they once occurred. Once common enough to be one of the first fish to be described by European explorers of Australia, but not seen for well over a century, this is the first modern day marine fish to be officially declared extinct. In October 2021, the endangered and very rare pink handfish (Brachiopsilus dianthus) was seen for the first time since 1999, in footage from a camera placed on the sea bed off Tasmania at a depth of Prior to this sighting, it had been assumed that this species was confined to shallow waters. The discovery that it has a greater range than previously thought may give cause for optimism regarding its survival.