Nepedia
Back to Discover
Advanced Reader
🧬

Handfish

life science Maturity 5-7 Next article →

Handfish, also known as warty frogfish, are a unique group of marine animals. They belong to the subfamily Brachionichthyinae. This group is part of the larger anglerfish family known as Antennariidae. Handfish are benthic creatures, which means they live on the very bottom of the ocean. They are quite different from most fish because they do not just swim. Instead, they use their fins to move along the sea floor.

This unusual way of moving makes them a fascinating subject for marine biologists.

The way a handfish moves is its most famous trait. They possess highly modified pectoral fins that look like small hands. These fins allow the fish to "walk" across the seabed. Their scientific name actually reflects this physical feature. It comes from the Latin word "bracchium," meaning arm, and the Greek word "ichthys," meaning fish.

FMIB 45786 Thymichthys verrucosus 2
FMIB 45786 Thymichthys verrucosus 2

Beyond their fins, they have other distinct body parts. They have an illicium, which is a modified dorsal fin ray located above the mouth. While other anglerfish use this as a fishing lure, the handfish version is short and does not seem to serve that purpose. They also have a crest on their back. This occurs because a flap of skin joins the second and third dorsal spines together.

Handfish anatomy includes a specific texture on their skin. Their bodies are covered in tiny, tooth-like scales called denticles. This texture is why many people call them warty anglers. There are 14 known living species within the subfamily Brachionichthyinae. These species are divided into five different genera. While they share many traits, their specific body shapes and sizes can vary. Most of these fish are slow-moving and stay close to the ocean floor.

Our understanding of handfish history has changed over time. An American ichthyologist named Theodore Gill first proposed them as a distinct family, Brachionichthyidae, in 1878. For a long time, they were considered the most basal family in their group. However, a phylogenetic study in 2025 changed this view. Scientists found they are actually relatively derived and are the sister group to the Rhycherinae. We also have evidence of handfish from the ancient past. Fossils from the Early Eocene period in Monte Bolca, Italy, show two prehistoric genera: Histionotophorus and Orrichthys.

Histionotophorus bossani
Histionotophorus bossani

It is surprising to find these fossils in Italy, since modern handfish are mostly found near Australia.

Today, handfish have a very specific home. They are found in the coastal waters of southern and eastern Australia. They also live around the island state of Tasmania. This region is very important because it is the most species-rich area for them. In fact, all but three of the 14 species are found in the Australian region. Because they live in such specific, restricted areas, they are very vulnerable to changes in their environment.

Sympterichthys politus
Sympterichthys politus

Their populations are often small, which makes it hard for them to recover if they face trouble.

Many handfish species are currently facing a high risk of extinction. For example, the spotted handfish was the first marine fish ever listed as critically endangered on the IUCN Red List in 1996. This species lives in the Derwent River estuary. It faces threats from the invasive Northern Pacific seastar. This seastar preys on handfish eggs and the sea squirts that form the ground where fish spawn. Other dangers include heavy metal contamination, urban effluent, and increased siltation. The smooth handfish was even thought to be extinct in March 2020.

FMIB 45786 Thymichthys verrucosus 2
FMIB 45786 Thymichthys verrucosus 2

However, that status was changed to "Data Deficient" in 2021 because scientists could not confirm it was truly gone.

Conservation efforts are vital for these fish. Currently, three species are listed as threatened under the EPBC Act and the IUCN. These include the spotted handfish, the red handfish, and Ziebell's handfish. In October 2021, scientists found a reason for hope. They spotted the rare pink handfish on a deep-sea camera off Tasmania. This was the first time it had been seen since 1999. This discovery showed that the pink handfish lives in deeper waters than anyone previously thought.

This wider range might help the species survive in the future.

682 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (4)
File:Histionotophorus bossani.JPG
Histionotophorus bossani.JPG
File:Brachionichthys hirsutus RLS.jpg
Brachionichthys hirsutus RLS.jpg
File:Sympterichthys politus.jpg
Sympterichthys politus.jpg
File:FMIB 45786 Thymichthys verrucosus 2.jpg
FMIB 45786 Thymichthys verrucosus 2.jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.