Now let’s get into the sexiest classification debate: where they live. Saltwater fish live in oceans, which cover 71% of the planet. Freshwater fish live in lakes and rivers, which cover less than 1%. Yet, 41% of all fish species live in freshwater. That’s like a party in a broom closet with 40% of the guests. How do they survive? They have super-kidneys that constantly pump out excess water. Fish are essentially living water filters. Gross? Yes. Amazing? Also yes.
And here’s a hilarious twist: some fish can switch between salt and freshwater. Salmon do this to spawn, which is like you deciding to live in a swimming pool filled with bleach for six months, then going home. Others, like the bull shark, are so tough they can hang out in both oceans and rivers. They’ve been found in the Mississippi River and a lake in Nicaragua. Nothing stops a bull shark except maybe a bigger bull shark—or a road sign.
The Bizarre Exceptions: Lungfish and Coelacanths
If you think fish are simple, meet the Lungfish. These weirdos have actual lungs and can drown if kept underwater too long. In dry seasons, they burrow into mud, wrap themselves in a cocoon of slime, and sleep for up to three years. Yes, three years of napping. That’s not a fish; that’s a college student after finals.
What Are The 7 Levels Of Classification For A Fish at Jamie Anthony blog
And then there’s the Coelacanth—a “living fossil” thought to have gone extinct with the dinosaurs. In 1938, a fisherman caught one off South Africa, and scientists nearly fainted. It has limbs-like fins and a hinged skull that opens like a trapdoor. It also gives birth to live young, which is weird because it looks like a mutant tire. If fish had horror movies, this would be the villain.
