Bichirs

Bichirs have a row of small fins along their backs that look like flagpoles and flags, hence their other name, the flagfish. Their  pectoral (chest), fins also grow from tiny “fans.”

The “flagpole and flag”arrangement is unique to bichirs and their closest relatives,the ropefish. Where other fish have one,or sometimes two,“normal” fins along the back,in bichirs each spine of the fin is separated from the others. Each carries a number of horizontal rays,creating a series of distinctive flagpoles and flags,which can number up to eighteen., The “fans”are

found in the pectoral (chest) fins that, instead of having the usual bone arrangement found  in other fish,contain two flat,platelike structures that look like miniature fans. The fins grow from these fans.

Ancient Survivors

Bichirs are believed to be primitive fish with a long history. Their ancestors probably first swam in the waters of the planet 400 million years ago,but had probably become extinct by 190 million years ago. The earliest bichirs appear much later; from around 145 to 65 million years ago,so there are a few pieces of this jigsaw missing. There could still have been bichirs around earlier than this,but scientists will not know, for sure unless they find their fossils. Today’s bichirs and ropefish can survive in poorly oxygenated water where other fish would struggle or die. They can do this because they have two lungs that allow them to gulp in air at the surface. In fact,bichirs have become so dependent on their lungs that they drown if they are prevented from surfacing for air.