Red handfish

Red handfish
Conservation status
Critically Endangered  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Lophiiformes
Family:	Brachionichthyidae
Genus:	Thymichthys
Species:	T. politus
Binomial name
Thymichthys politus (Richardson, 1844)
Synonyms
Cheironectes politus Richardson, 1844 Brachionichthys politus (Richardson, 1844) Sympterichthys politus (Richardson, 1844)

The red handfish (Thymichthys politus) is a species of marine

The red handfish has the genus name Thymichthys which is a combination of thymos, meaning "warty growths", and ichthys, which means "fish". This is an allusion to the warty protuberances on the skin of this fish. The specific name, politus, means "polished", an allusion Richardson did not explain but it is thought to be to the smoothness of its skin to the touch or its bright colouration.^[5]

Description

The red handfish is distinguished by its small, flattened wart-like protuberances that cover its body and red colouration. Two colour morphs exist, a bright red morph with red colour on both body and fins, with a black line separating the white fin edges and a mottled morph with pink body covered in many red patches, with translucent pink fins expressing some bright red patches. They measure an average standard length of 61.4 mm (2.4 in) and an average total length of 80.1 mm (3.2 in).^[3] They use their hand-like fins to crawl rather than swim.^[6]

Ecology and behavior

Distribution and habitat

Historically, the species was found in multiple subpopulations in Tasmania, including

Their limited range is attributed to the low reproduction and dispersal rate. Unlike other fish they recruit directly on the benthos.^[7] Females lay their eggs at the base of seagrass from august through to October. Each egg mass contains 30- 60 eggs that are connected by tubules bound together. These eggs are then guarded by the adults until they hatch.^[8]

Diet

Little is known about their diet but that it consists of animals that live in the benthos. Their diet consists of small crustaceans and polychaete worms.^[9]

Conservation

In November 2023, researchers at Tasmania’s Institute for Marine and Antarctic Studies (IMAS) found a cluster of 21 yellow eggs in one of their tanks for red handfish. One of the researchers said “We’re delighted to announce the safe arrival of 21 baby red handfish.” This is the second time red handfish have been breed in captivity, with the previous time being in 2021.^[10]

Threats

General threats to red handfish include small, very fragmented populations and local increases in density of native purple urchins. Native purple urchins overgraze the seaweed habitat required for shelter and spawning for the red handfish. Summer observations of low seaweed on urchin barrens suggest that loss of seaweed habitat might represent a key threat to long term viability of the population In addition, the close vicinity of urban development increases the risk of nutrient runoff, pollution, siltation, and turbidity. This results in habitat degradation through the ruin of the red handfish preferred seaweed habitat. Loss of spawning substrate limit the red handfish as to where their eggs can attach resulting in the eggs being lost to the current. Limitations include difficulty spotting the species among its habitat. Red handfish may face severe pressure due to direct environmental consequences of warming coastal waters, including potential implications on reproduction, egg development, feeding, and escape reaction, which are currently unknown.^[1]

Status

The red handfish is classed as