The animal kingdom is constantly surprising us. From mammals that lay eggs and flightless birds, it seems that they are always finding a way to defy classification.
Fish that walk on land are an example of this. They are able to breathe air for short periods, propel themselves across the ground with intent, and some are even able to climb. While they turn everything we think we know about nature upside down, these fish provide an interesting insight into the first animals to emerge from the ocean and walk on land.
5 fish that walk on land
Scientific name: Oxudercinae
Where they’re found: Africa, Polynesia, Australia
These are the fish you most commonly think of when you think of fish that walk on land. Mudskippers are greenish-brown with fins that are toward the front of their body, and placed underneath, which allows them to gain traction when walking on land. They can grow to be about 12 inches long based on species.
Facts about Mudskippers
- Mudskippers are able to move their eyes independently. This allows them to see both the surface and underwater at the same time.
- Mudskippers use their pelvic fins to help them climb, and they are able to jump 2 feet.
- A mudskipper can die if it spends too much time underwater.
2. Snakehead fish
Scientific name: Channidae
Where they’re found: Asia and Africa, and in other countries as invasive species
These fish have an elongated body, with a head reminiscent of a snake’s. They are capable of breathing air with their gills. When fully grown they eat other fish, frogs, and occasionally rodents. These fish “walk” by undulating across the land instead of using fins.
Facts about snakehead fish
- Their respiratory system gives them the ability to survive for several days on land.
- They often hunt in schools, aggressively hunting their prey.
- They are very sensitive to salt in the water and are unable to handle anything over 10 parts per million.
3. Epaulette shark
Scientific name: Hemisciyllium ocellatum
Where they’re found: Australia, New Guinea
This small tropical shark has an elongated body and 2 dorsal fins. They are cream or greyish in color, with a large black spot directly behind their pectoral fins. They feed on worms and bony fish, preferring to hunt at dawn and dusk.
Facts about epaulette shark
- They move their bodies in a way similar to a salamander, which is what allows them to move across the sand from tidepool to tidepool.
- They are able to survive for hours in conditions with very little oxygen. In laboratory conditions, they have survived for as long as an hour with no oxygen at all.
- They frequently choose to walk across a sandy substrate underwater rather than swim.
4. Climbing gourami
Scientific name: Anabantiformes
Where they’re found: China, South East Asia, Africa
These are greyish, ray-finned fish, which possess an organ, called the labyrinth organ which allows them to breathe on land. They support themselves on their gill-plates and push themselves across the ground using their tail. They resemble perch, although they are not related.
Facts about climbing gourami
- Although it has not been recorded, there is anecdotal evidence pointing to the ability of the Climbing gourami to climb trees.
- There are 34 species in this group, and they prefer to live in freshwater. If conditions become unfavorable, they will leave in search of a more suitable body of water.
5. Walking catfish
Scientific name: Clarius batrachus
Where they’re found: South East Asia
This freshwater catfish has an elongated body with the sensory barbels typical of all catfish, they grow to be around 12 -20inches long. They are grey or brown and do well in brackish water with little oxygen. They often live in canals or ditches, feeding on weeds, and invertebrates.
Facts about walking catfish
- They are able to stay out of the water for up to 30 hours if they are searching for a new habitat.
- They were introduced into Florida, and are now an invasive species in the Everglades, although they are undesirable they have not had any noticeable negative effects on the native species.
6. Mangrove rivulus
Scientific name: Kryptolebias marmoratus
Where they’re found: North, South, and Central America
These are tiny fish, ranging from 2.5 to 6 cm. They are slender, with a body that is flattened dorsally. They can be dark brown, green, or mottled with some orange. They eat insects, small worms, and occasionally their own eggs.
Facts about Mangrove rivulus
- These fish are the only example of self-fertilizing hermaphrodites. They frequently reproduce through self-fertilization.
- The mangrove rivulus is capable of spending an incredible 66 days out of water. They spend much of their time on land in fallen logs.
- They can handle a wide range of temperatures and salinity and is currently a part of toxicity studies due to its ability to handle pollution.
Scientific name: Polypteridae
Where they’re found: Africa
There are 11 recognized species of Bichirs. They are elongated fish, with a series of dorsal finlets that vary in number. They can range from 9.8 inches to 39 inches depending on the species. These predatory fish consume a diet of insects and small crustaceans. They inhabit shallow floodplains and estuaries. They are uniquely suited to water that is low and poorly oxygenated.
Facts about Bichir
- Bichirs have a pair of lungs and are able to stay out the water for hours at a time provided their skin stays moist.
- These fish have an overbite which allows them to suck in prey when they open their mouths.
- Since this is a fish that can walk on land, scientists used it in an experiment to see what happens if a fish is raised on land. They were kept in special low water environments and misted to keep them moist. Scientists were able to note structural changes as well as improved mobility.