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Red Handfish — The Walking Fish With Fewer Than 100 Left on Earth

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Bizarre Sea Creatures

By Blane Perun

6 min read

What is the red handfish?

The red handfish (Thymichthys politus) is a critically endangered benthic fish found only in a tiny area of reef off southeastern Tasmania, Australia. It is 13 cm long, moves by walking on modified hand-like pectoral fins rather than swimming, and has a distinctively angry-looking face and vivid red colouration. There are estimated to be fewer than 100 individuals remaining in the wild — making it one of the rarest marine fish on Earth. Its low reproductive rate, dependence on specific green algae for spawning, and extremely limited range make it acutely vulnerable to any environmental change.

Quick facts

Scientific name

Thymichthys politus

Length

~13 cm

Range

Southeastern Tasmania, Australia — extremely restricted

Population

Estimated fewer than 100 individuals

Locomotion

Walks on modified pectoral fins — rarely swims

Colouration

Vivid red with darker markings; white belly

Reproduction

Spawns on green algae stalks; very low reproductive rate

Conservation status

Critically Endangered (IUCN)

The red handfish has one of the most precarious existences of any marine vertebrate. It is not endangered because of overfishing or a dramatic habitat collapse — it was always rare, always restricted, always dependent on a specific narrow set of conditions. Its survival was always marginal. What human activity has done is reduce its already thin margin even further, to the point where a single bad season, a disease outbreak, or a targeted poaching event could functionally end the species in the wild.

Why it walks instead of swims

The red handfish belongs to a family of fish — the Brachionichthyidae, or handfishes — that evolved modified pectoral fins adapted for walking on the seafloor rather than swimming through the water column.

The pectoral fins are positioned like arms, with an elbow-like joint that allows the fish to “walk” along the substrate in a motion that genuinely resembles quadrupedal locomotion. The fish uses this to move slowly through rocky reef habitat, hunting small worms and tiny crustaceans. It rarely swims — and when it does, it is not particularly good at it. This extreme sedentariness means that an individual red handfish may spend its entire life within a few square metres of reef. It also means that if that patch of reef is damaged, that individual cannot simply relocate.

<100

Estimated wild individuals remaining

13 cm

Adult body length

1800s

Year of first documented sighting near Port Arthur, Tasmania

The spawning problem

Red handfish reproduce at a rate that would barely sustain a healthy population in ideal conditions. In degraded conditions, it is barely sufficient at all.

Females lay small clusters of eggs — typically around 80 at a time, which is very low for a fish — directly onto the stalks of specific green algae. Both parents reportedly guard the eggs until hatching. The juveniles that emerge are miniature adults — there is no pelagic larval stage, meaning the young do not drift and settle elsewhere. They stay exactly where they were hatched. This reproductive strategy provides no mechanism for range expansion or recolonisation if a local population is lost.

Conservation status: The red handfish is listed as Critically Endangered on the IUCN Red List. The Institute for Marine and Antarctic Studies (IMAS) in Tasmania leads active monitoring and breeding programs. Captive breeding has been attempted as an insurance policy against wild population collapse.

“Fewer than 100 animals, each living its entire life in a few square metres of reef, unable to move if that reef is damaged. The species was always marginal. What we’ve done is remove the margin entirely.”

— Blane Perun, TheSea.Org

Frequently asked questions

How many red handfish are left?

Estimates suggest fewer than 100 individuals remain in the wild. The population is restricted to a very small area of reef off southeastern Tasmania. Because adults do not move long distances and juveniles have no dispersal stage, any local population loss is permanent — the area cannot be recolonised from elsewhere.

Why does the red handfish walk instead of swim?

Its pectoral fins evolved into hand-like appendages adapted for walking on the seafloor rather than generating propulsion through water. This is a characteristic of the handfish family (Brachionichthyidae). The fish moves slowly through benthic reef habitat hunting small prey. Swimming is possible but rare and inefficient — walking is its primary means of locomotion.

Where does the red handfish live?

Only in a very small area off the coast of southeastern Tasmania, Australia. It prefers rocky reef habitat with specific algae and a combination of substrate, depth, and water temperature that is extremely localised. No verified populations exist anywhere else in the world.

Why is the red handfish so endangered?

Its combination of characteristics makes it uniquely vulnerable: extremely limited range, sedentary lifestyle with no dispersal mechanism, low reproductive rate, dependence on specific algae for spawning, and sensitivity to habitat disturbance. Human pressures — coastal development, invasive species, sedimentation — have reduced its already thin margin of survival to near zero.

Is the red handfish related to the red-lipped batfish?

Both are in the order Lophiiformes (anglerfishes and allies) and both walk on modified fins, but they are in different families. The red handfish is in Brachionichthyidae; the red-lipped batfish is in Ogcocephalidae. They evolved walking locomotion independently as adaptations to benthic life.

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