39 Important Facts About Fishes & Why They Need to Be Protected

At birth, Halibut have an eye on each side of the head and swim like a salmon. After 6 months, one eye migrates to the other side, making them look more like flounder. At the same time, the stationary-eyed side darkens to match the top side, while the other side remains white.

2. In 2014, during the Super Bowl and Puppy Bowl, Nat Geo Wild showed the "Fish Bowl", a 4-hour clip of a goldfish swimming in a bowl.

3. Crocodile icefish doesn't use blood to transport oxygen, it absorbs oxygen directly from water using its skin

4. Discarded pet goldfishes can grow very large in the wild and they are causing serious environmental problems.

5. Sardine isn't actually a species of fish but rather a generic name given to various small, oily fishes within the herring family of Clupeidae.

A koi fish named Hanako lived for 225 years.

7. Doctors in Ancient Rome used an early form of electrotherapy to successfully treat neurological conditions such as epilepsy and migraines. They administered the charges by placing electric torpedo fish on the patient's head.

8. Despite the stereotype of a very short life, with proper care, an average goldfish can live up to 10 years as pets, and over 25 years in the wild. The longest recorded lifespan for a goldfish was 43 years.

9. In 2013, a genetic test of fish in restaurants and supermarkets showed 84% of Sushi restaurants in the US mislabeled and replaced tuna with Escolar, a fish known to cause prolonged, uncontrollable oily anal leakage.

10. The largest Blue Marlin ever caught on rod and reel weighed 1,800 lbs, and inside its belly, they found a Yellowfin Tuna that weighed over 155 lbs.

In April 2015, scientists observed several armored catfishes climbing walls of a cave in Ecuador. It was also the first time scientists found catfishes to have evolved to live in water bodies underground.

12. The goliath tigerfish is said to be a bigger and deadlier version of the piranha. It has 32 teeth that are of similar size to those of a great white shark. It has been known to attack humans and even crocodiles. It has only ever been caught by a handful of fishermen due to the danger it poses.

13. Some horse owners put goldfish in the water troughs to keep them free of insects like mosquitoes and algae.

14. There are more species of fish found in the Amazon river than they are recorded in the entire Atlantic ocean.

15. There is a fish named Needlefish that can jump from the water and stab people at speeds of up to 37 mph, with multiple human fatalities on record.

In 2013, a 500lb bluefin tuna fish was sold in Japan for $1.8 million.

17. Goldfish have teeth in the back of their throat.

18. In 2013, a man named Naylor in Blackpool made a lifejacket for a goldfish named Einstein that wasn't able to swim after falling ill.

19. Freshwater fish only "drink" water through their skin via osmosis, while saltwater fish also drink water through their mouths.

20. The Coelacanth is a prehistoric fish which is related to reptiles and mammals more than modern fish. It was thought to have gone extinct 65 million years ago until a fisherman caught one in 1938.

Up to 40% of tuna imported to the U.S. from Thailand is illegal or unreported, followed by up to 45% of Pollock imports from China, and 70% of salmon imports.

22. The notion that goldfishes have a memory span of only few seconds is nonsense. In fact, they can be trained to react to light signals and perform tricks.

23. The blood of eels is more poisonous than some snake venom, but cooking or digesting the blood renders it harmless.

24. Goldfishes were originally silver. They were bred by the imperial family of Song Dynasty in ancient China until they became yellow because they really liked yellow.

25. Seahorses engage in an eight-hour courtship dance which includes spinning around, swimming side by side and changing colors.