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// The Dusky-gilled Mudskipper 
// Story: Nature is So Fascinating 
// by Powderjaggy 
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Photo credit: CheongWeei Gan


"Hello, class. Today we will be meeting some of my fishy friends. They are dusky-gilled mudskippers. But even though they are fish, you'll see that I haven't filled their tank completely with water. This is because mudskippers actually spend a lot of their time on land! They are able to breathe both in air and in water by using their gills, skin, and the insides of their mouths. However, these body parts need to be kept wet to work properly, so mudskippers live in swamps and on mud flats, often close to where rivers flow out to the sea.

"Life underwater is very different from life on land—oh, yes, Silverstream, I'm sure you would know! For example, fishes do not have necks like we do, so they cannot turn their heads to look around themselves. In the water, a fish can simply turn their whole body around until they can look in the direction they want, but it would be most troublesome if they had to do that on land! 

"That's why mudskippers have eyes that sit adorably on top of their head. They can rotate their eyes to see almost all the way around, above, and below themselves. Sometimes I wish I had eyes like a mudskipper... it would be much easier for me to see if something scary was coming my way. To keep their eyes moist, mudskippers blink, which is something that other fishes can't do.

"Mudskippers feed on insects, snails, and other small critters that they find on mud flats. Eating on land presents them with another problem. Most fishes don't have a flexible tongue to help them swallow food, like we do. They don't need one, because they can wash their food down by sucking in water along with it. But mudskippers need to feed on land without a flexible tongue, and they have a very interesting way of doing so.

"A hungry mudskipper stores water in their mouth when they come onto land. If they see something they want to eat, they will spit out the water onto their food, then suck it all back into their mouth, swallowing their food with it. This way, they can feed by suction even when they're not in the water. Those wouldn't be very nice table manners for a pony, but it is how mudskippers do things.

"As you might have noticed already, mudskippers can move around on land by pushing themselves along with their pectoral fins—the paired fins sticking out on either side of them. When they want to move more quickly, they can also jump by launching themselves forward with their tails. Some mudskippers, including dusky-gilled mudskippers, are even able to climb! They do this by sticking to surfaces with their pelvic fins, the paired fins on their underside. I've placed a few branches and sticks in this tank for them to climb on.

"Dusky-gilled mudskippers have been seen getting around in a way that no other fish has. They are able to use their tails to skip quickly across the surface of the water. The pools found on mud flats are often not deep enough to hide them from predators, so skipping across the water is probably a faster and safer way for them to escape to their burrows than swimming.

"Oh dear, I haven't mentioned that mudskippers dig burrows, have I? Their burrows are very important to them. Mudskippers are so used to moving around on land that they aren't as good at swimming as other fishes, so when the tide comes in and covers up the mud flats, they retreat to the safety of their burrows. But because the water inside doesn't flow much and is not exposed to air during high tide, the oxygen levels inside the burrow soon become very low. 

"That is why mudskippers also dig a special air chamber as part of their burrows, allowing them to breathe while they're inside. An essential part of every mudskipper's day is gulping mouthfuls of air during low tide that they bring back to their burrows, refilling the air chamber with fresh air.

"When it's time for mudskippers to breed, a male mudskipper spends a lot of his time keeping other males away from his territory. He then tries to get the attention of nearby females by leaping into the air and spreading his fins. If a female accepts him as her mate, she will follow him into his burrow, where she will lay her eggs in another air-filled chamber that the male has specially prepared.

"The male works hard to take care of the eggs by himself, bringing them fresh air every day. When they are ready to hatch, he will wait for a high tide to cover the burrow, then remove the air from the egg chamber. The baby mudskippers quickly hatch once the chamber fills up with water, and swim out of the burrow to start their own lives.

"Oh, would you look at the time. I really should bring my friends here back to their homes on the mud flats, before their burrows are submerged underwater. Have a lovely day, everycreature, and stay kind to each other."