Ten Amazing Fish Facts

Esther’s writing prompt: November 12 : Fish

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This is not a super fact but a collection of interesting facts about Fish. They are not very important facts but amazing facts.

Freshwater fish Riffle minnow (Alburnoides bipunctatus) underwater photography. Minnow in clean water and nature habitat. Natural light. Lake and river habitat. Wild animal. Underwater photo of fish. | Ten Amazing Fish Facts
Minnows Asset id: 1182854671 by Rostislav Stefanek

Most Fresh Water Fish would die from dehydration if put in Sea Water

Most freshwater fish would die from dehydration if placed in seawater due to a process called osmosis. The same is true for saltwater fish placed in freshwater.  There are a few exceptions. So called euryhaline species are able to more or less handle both freshwater and seawater, an example is salmon. It is also why freshwater fish native to oceanic islands like Hawaii are euryhaline species. Freshwater fish that are not euryhaline species cannot travel to oceanic islands.

What is a Fish?

A fish is a vertebra (has a backbone and a brain protected by a braincase) that is aquatic, lives in water, has gills, fins, scales and is cold blooded. Dolphins, whales, jellyfish, and starfish are not fish.

Some fish have both gills and lungs

Lungfish have both gills and lungs. Their unique respiratory system allows them to breathe underwater with their gills and also breathe air from the surface with their lungs. Some species of lung fish can survive on land for several months.

Lung fish resting close to the bottom of the sea. The exact species is Neoceratodus forsteri (Australian lungfish).
Queensland lungfish, Mitch Ames, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons

Fish Can Be Raining from the Sky

Tornadoes over water have sometimes picked up both water and fish causing fish to rain down over land.

The illustration depicts a tornado / waterspout over land with lots of orange fish raining down.
Fish raining from the sky. Picture generated with the help of ChatGPT

Mudskippers the land dwelling fish

Mudskippers are fish that spend most of their time on land. It can walk on land, jump, and climb trees, by using their strong pectoral fins like legs and their tails as a lever. They breathe air through their skin and gill chambers. Below is a four minute video featuring mudskippers.


Fish the First Vertebra on Earth

Fish appeared more than 500 million years ago during the Cambrian period. They are believed to be the first vertebrates on Earth. They lay the foundation for the diverse array of vertebrate life that has since populated the planet’s ecosystems.

Some Fish can make Light

Anglerfish are deep sea fish that produce their own light using bacteria. The dangling glowing light attracts prey. Some species of angler fish live only 200 meters down in the sea while other species live as far down as 3,300 meters (11,000 feet).

Angler fish on background realistic illustration isolate. Scary deep-sea fish predator. Deep sea fish monster. | Ten Amazing Fish Facts
Angler fish on background realistic illustration isolate. Scary deep-sea fish predator. Deep sea fish monster. Asset id: 2134226987 by Konstantin G

Some Fish know how to use Tools

Wrasse are fish that use rocks as anvils to crack shells. They grab hard-shelled prey like crabs and mollusks, swim to a rock or coral, and repeatedly strike the prey against the hard surface to break it open. This is a form of  tool use.

This Wrasse is a long blue and orange fish.
Cuckoo wrasse. Olivier Dugornay, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0&gt;, via Wikimedia Commons.

Megalodon

The largest fish that has ever lived is likely the extinct shark Megalodon, estimated to have reached lengths of up to 70 feet and weighing 50-70 tons. The Megalodon was a giant shark believed to have gone extinct 2.6 million years ago, just in time for the appearance of our ancestors Australopithecus and Homo Habilis. They made a horror movie about a Megalodon that survived until modern times. It is called “The Meg”.

Megalodon shark with its mouth wide open pursuing two whales much smaller than it.
Artistic impression of a megalodon pursuing two Eobalaenoptera whales. Karen Carr, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons.

Surströmming (Fermented Baltic Herring) a North Swedish Delicatessen

In 1987 I was selected by my University, Uppsala University in Sweden, to be part of a university level exchange student program. The exchange program was between Uppsala University and Case Western Reserve University in Cleveland, Ohio. In total we were six Swedes (two from Uppsala). I was studying Engineering Physics in Sweden. In the US, I would continue studying Electrical Engineering because the Swedish Engineering Physics program was very similar to the Electrical Engineering program at CWRU. One day we invited the other students to a Surströmming party. When we opened the cans, the American students headed for the windows and opened them. I should say there were other things to eat.

The fermented herring Surströmming from Sweden is often considered as one of the most unappetizing foods in the world. Just ask Google AI or ChatGPT this question, “what is the most unappetizing food in the world”, and you’ll see. The three top unappetizing food according to ChatGPT are Hákarl (Fermented Greenland Shark) – Iceland, Surströmming (Fermented Baltic Herring) – Sweden, and Casu Marzu (Maggot Cheese) – Sardinia.

I grew up with this food, and I don’t think it is unappetizing. It might not be beef bourguignon or trout almondine, but it isn’t bad. The problem is that the smell of Surströmming is not very pleasant and it is strong. However, it tastes quite different from the smell. It tastes like pickled herring with the addition of something sour like lemon. The taste is much better than the smell, which is why you should open the cans outside and then bring them in once the smell has settled. We did not do that because our party was partially a prank. Well, if you don’t like pickled herring, then you won’t like this either.

Ten Amazing Fish Facts
Four Swedes inviting Americans to a fermented herring party. Fermented herring is a north Swedish specialty. Unfortunately, all the Americans experienced a culture shock from the fermented herring. I am the guy smelling the fermented herring can.



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