Did You Know? Air breathing fish can drown!

Yes, some fish can actually drown if they don't come up for air regularly! Below is a picture of the Arapaima, which is native to South America but which has also been introduced for fishing in Thailand and Malaysia.

This fish is an air-breather, using its swim bladder, which is rich in blood vessels and opens into the fish's mouth. This is an advantage in oxygen-deprived water that is often found in the Amazon River. The Arapaima is therefore able to survive in shallow waters with dissolved oxygen as low as 0.5 ppm.

Generally, Arapaima must come up for a gulp of air about every 15 minutes.  Consequently, sport fishermen who intend to release the fish once caught must be careful not to get their lines tangled around underwater objects in such a way that it prevents the fish from surfacing for air.

These fish can be extremely challenging to catch since they have been known to reach over 8 feet long and weigh in at over 200 pounds!

There are various other fish that also must come up for air, else they drown. Yes, surprising, but true!

Below is another extraordinary fish - the mangrove rivulus, also known as the mangrove killifish. It is native to the Americas and is about two inches (five centimeters) long. Look very closely to find the little fish peeking out from its lair in a log!  [photo is from National Geographic News]

This tiny Western Atlantic fish does something never before seen: It makes like a bird, living in mangrove wood for months at a time. It can also live out of water for up to 66 days!

Studies suggest that the animals can breathe cutaneously—through their skin—as long as they remain in a moist environment. To increase the time they can do this, the fish fill their gill systems with a mass of cells. Otherwise, the delicate gill plates would collapse and fuse together.

There are many other Amphibious fish out there. Mudskippers are generally well known to the general public. They also purposely walk onto land with specialized fins that act as legs of a sort. You can also buy aquarium fish that can live out of water and breath air. (Or would that be Terrarium fish instead, eh?)

It is such a wonderfully strange world of nature out there, isn't it!?

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Note: information for the text of this article has been gleaned from several sources including National Geographic News,   Wikipedia,   Marine biology oceanography at suite 101,  and   National Wildlife Magazine.