Mudskipper
Weirdness 8/10

The fish that walks, climbs, and breathes on dry land

This is a fish that spends most of its life out of the water — walking, climbing, and even fighting on land.

📋 Fact File
🐾 Fish🍽️ Carnivore
📏 Size
About 10-30 cm (4-12 in) long depending on the species
About as long as your hand
Lifespan
Up to about 5 years
🟢 Least ConcernThese mud-loving fish are still widespread across warm coastal swamps.
🤔 Guess first

Which one is REALLY true about the Mudskipper?

The short version

ages 9–12

The mudskipper is a fish that lives mostly out of water, using arm-like front fins to walk and climb. It breathes by holding water over its gills and absorbing oxygen through its wet skin and mouth, has independently-moving eyes on top of its head, and does push-ups to impress mates.

📏 How big is it, really?
Mudskipper
30 cm
Mudskipper
a 7-year-old
1.2 m
🧒

You could line up about 4 of them along a 7-year-old!

Why it's so weird

  • The Mudskipper spends most of its life out of the water, walking and climbing on dry land.
  • The Mudskipper uses its strong front fins like little arms to pull itself across the mud and skip surprisingly fast.
  • The Mudskipper breathes air by holding a mouthful of water over its gills and absorbing oxygen straight through its wet skin and mouth, almost like a frog.
  • The Mudskipper has eyes that sit on top of its head and move independently, giving it a nearly complete view of and rivals.
  • The Mudskipper does little push-ups and leaps into the air to impress mates and defend its muddy territory.

The full story

This is a fish, but it spends most of its life completely out of the water. Meet the mudskipper, an animal that walks, climbs, and even fights on dry land. Using its strong front fins like little arms, it pulls itself across the mudflats and can skip and hop surprisingly fast. To breathe air, it holds a mouthful of water over its gills, and it also absorbs oxygen straight through its wet skin and the lining of its mouth, almost like a frog. Its eyes sit right on top of its head and move independently, giving it a nearly complete view to spot predators and rivals. Males even do little push-ups and leap into the air to impress females and defend their muddy territory. A fish that decided the land just looked more interesting. Follow for more weird animal facts.

🔬 The science — how & why

On land, a mudskipper still needs oxygen but can't pump water over its gills, so it uses three tricks at once. It carries a mouthful of water trapped in sealed-shut gill chambers so the gills stay wet and keep working, and it also soaks up oxygen straight from the air through its thin, wet, blood-rich skin and the lining of its mouth, the way a frog does. This only works while the skin stays damp, which is why a mudskipper keeps rolling in wet mud. To 'walk,' it swings both strong front (pectoral) fins forward at the same time, like a person on crutches, because those fins have extra-big muscles and a beefed-up shoulder to push its body along.

📚 Source: OIST — To walk, you only need fins (and maybe a sense of adventure)
🔎 How do we know?

Scientists at Japan's Okinawa Institute of Science and Technology used micro-CT (µCT) X-ray scanning, with iodine staining to reveal soft tissue, to build 3D reconstructions of the barred mudskipper's fins and showed it 'crutches' by swinging both pectoral fins forward together.

📚 Source: OIST — To walk, you only need fins (and maybe a sense of adventure)
Learn

Check what you learned

No score, no pressure — just see what stuck. Tap Real or Fake.

The Mudskipper spends most of its life out of the water, walking and climbing on dry land.

The Mudskipper can switch its body to run on plant sugar when oxygen runs out, almost like a plant.

The Mudskipper uses its strong front fins like little arms to pull itself across the mud and skip surprisingly fast.

🍎 Teacher or parent? Print a Mudskipper research worksheet or open the lesson hub.

Watch the 45-second version

Mudskipper gallery

Mudskipper 1Mudskipper 2Mudskipper 3