Mudskipper

On land or in the water, fish or amphibian? Mudskippers can use both habitats: they crawl across the land at low tide and even climb trees.

Characteristics

What does a mudskipper look like?

Mudskippers are fish that belong to the goby family and thus to the order Perciformes. The fish, which are 10 to 30 centimeters long, have the typical shape of gobies: They have a thick head from which their eyes protrude – similar to a frog’s. In addition, they are very mobile. Like all fish, they have fins. However, the pectoral fins are greatly thickened and have equal arms. They are used by the animals to crawl forward over the muddy ground.

In some species, even the pelvic fins are transformed into lever-like, arm-like structures. Mudskippers breathe through gills. Since they mainly live on land or in shallow water at low tide, their gill cavity is only connected to the outside world by a narrow gill slit. Once the animals are on land, they can close the gap. This prevents the gills from drying out.

So that their sensitive eyes do not dry out when they go ashore, the animals have skin pockets under their eyes in which liquid is stored. They pull their protruding eyes back into their heads to wet them and supply them with the water from the skin pouch.

Where does the mudskipper live?

The different species of mudskipper are found in the tropical seacoasts of Africa and Asia. Mudskippers live on the coasts and there in the mangrove swamps, i.e. between the roots of the mangrove trees and in the mud of the ground. They live in the sea and brackish water, but also migrate into freshwater, for example in estuaries, in search of food.

What types of mudskipper are there?

There are probably several hundred different species of mudskipper. These include, for example, the common mudskipper, the mangrove mudskipper, and the swamp mudskipper. The loggerhead mudskippers are closely related: They are purely sea creatures and do not go on land.

How old does a mudskipper get?

Mudskippers kept in the aquarium lived up to five years. How long the fish live in nature is not known.

Behave

How does a mudskipper live?

Mudskippers live in two different worlds: they live in water like normal fish, but they also go on land – like frogs. At low tide, they crawl forward and hop across the silt bottom. They push themselves off the ground with their tails and shoot up – hence the name “mudskipper”. Although they can swim, they like to stay on land and even crawl up the low branches of mangrove trees.

However, most of the time they sit quietly in shallow water with the head and part of the body sticking out above the water surface, the tail usually lying in the water. Because they don’t breathe with their gills like fish normally do during this time, they store seawater in their enlarged jaws. They also gasp for air with their mouths. In addition, they can absorb oxygen through their skin, which is heavily supplied with blood, and through the bulges in their mouth and gills.

Mudskippers seek shelter in burrows that they dig underwater in the soft ground. These can have up to four outputs. So that the animals have enough air to breathe in the caves, they build up a supply of air: they carry air bubbles into their cave with their mouths, so that an air bell forms there.

Mudskippers live in groups. However, each animal has its own territory, which extends around its den.

Friends and foes of the Mudskipper

Predatory fish, birds, but also water snakes prey on mudskippers. They are therefore among their greatest enemies.

How does the mudskipper reproduce?

There is probably something like a courtship display among mudskippers, in which the males court the females. These eventually lay the eggs in their den where they can mature safely and securely. Eventually, the larvae hatch and grow into young mudskippers.