37 Things That You Probably Didn’t Know About Fish

Fish – not just something that goes with your chips! They’re an amazing group of weird and wonderful creatures. As the premier seafood restaurant on Hilton Head Island, we decided to compile 37 of the best fish facts; so dive in and learn about some of the things that make fish special. From flying fish to glowing fish and fish that aren’t even fish, impress your friends with your knowledge of fun fish facts.

1. The word fish is both singular and plural.

In the English language, fish is a singular term when used for a single example of any fish species. However “fish” can also refer collectively to many kinds of fish.

2. Fish are the oldest inhabitants on earth.

Fish have been present on Earth for the last 450 million years. They were present long before the dinosaurs roamed the Earth.

3. There are 30,000 species of fish.

There are more species of fish than mammals, amphibians, reptiles, and birds put together. That’s a lot of fish! It’s not surprising, inasmuch as water covers half of the surface of the planet, leaving fish lots of room to develop into lots of different species. What’s more, there are probably thousands more species of fish that we haven’t even discovered yet.

4. Each fish is an individual with their own personality.

When we think of fish, we often see them as a collective, without much variation between individuals. Recent research, however, is showing that fish do, in fact, have their own unique personalities. For example, some are bolder and more eager to explore while others are more timid and tend to take less risks than their peers. Just like us, personality traits between fish vary depending on the genes they inherit from their parents and their own life experiences.

5. American lobsters have longer life spans than both cats and dogs, living over 20 years.

6. Goldfish can live for decades.

The oldest known goldfish, “Goldie,” died in 2005 at 45 years of age. The second oldest goldfish was “Tish,” who died at 43.

7. Sailfish, swordfish, and marlin are the fastest fish in the ocean, reaching speeds of up to 70mph, which is faster than the speed limits on most highways.

8. Fish are cold blooded.

That doesn’t mean they’re mean! Unlike humans, who are warm blooded mammals, fish are cold blooded which means that their body temperature is not a constant temperature (such as a 98.6-degree human) but it will acclimate to the water around them.

9. Fish breathe through gills.

Fish breathe oxygen, just like mammals, but not the same way. Instead of lungs, they take oxygen out of the water by filtering it through their gills, which are flaps on the side of their bodies. Fish can even drown in water if the water doesn’t have enough oxygen.

10. A special fish radar helps in navigation.

Fish have a special sense organ, the lateral line, which is like radar that helps them navigate in dark or murky water.

11. Fish can be found in almost every type of water habitat.

Fish can live high up in mountain streams, in hot desert springs, in drying mud, in tropical ponds, and deep in the ocean. Some fish thrive in warm waters, while others need cold to live. The Antarctic icefish can survive in water below 32 degrees F because their blood contains special chemicals that keep their bodies from freezing.

12. A fish is a vertebrate, an animal with a backbone, which has adapted to life in the water.

13. Not all underwater animals are fish.

Whales and dolphins are mammals. A mammal is a vertebrate that produces milk to feed their young.

14. The diet of a fish depends on what type it is.

Some fish are herbivores who eat aquatic plants and algae. Others are carnivores, who eat other fish, insects, crabs, frogs, snakes, even squid or octopus. Some sharks are predators who hunt for prey. Many fish are omnivores, feeding on both plants and animal life.

15. Some fish aren’t fish

The name fish can be a bit misleading, as some creatures we call fish aren’t fish at all. Jellyfish, for example, belong to a classification called phylum Cnidaria, a type of invertebrate. Starfish are something called an echinoderm, cuttlefish are a type of cephalopod, and crayfish are crustaceans.

16. Fish have taste buds all over their bodies.

Like us, fish need taste buds so they know whether or not what they’re eating is dangerous or poisonous. But fish taste buds aren’t limited to their mouths; they have them all over the body, their fins, and their barbels (the long sensors you see on some fish).

17. Flying fish don’t actually fly.

Instead of flying, they glide at high speeds, staying in the air by allowing the wind to flow over their fins. Once they slow, they fall back into the water. Flying fish can glide for long distances too, usually up to 50 meters. However, scientists have observed them gliding further, up to a distance of 200 meters. These fish can also reach heights of up to 20 feet.

18. Some fish live at 7,000 meters deep.

We’re used to seeing fish in ponds and rivers, but some fish live so deep down in the ocean you wouldn’t be able to see them without a special submarine. These fish are especially adapted to live in total darkness at immense pressures, such as the angler fish, whose fluorescent head lamp helps to lure prey into its jaws.

19. Pufferfish makes for a dangerous meal.

In Japan, they’re served as the delicacy, fugu. The problem is that the puffer fish’s flesh is very poisonous, with a single pufferfish having enough poison to kill 30 people. It has to be prepared with great care.

20. Pufferfish chefs have a license of their own.

The license certifies them as having completed government regulated training on the proper preparation of fugu. The final exam for their training involves making a complete dish of fugu and then eating it themselves. If they’re unaffected, they pass. If they are affected, whether fatally or not, they fail. Any restaurant that serves fugu must publicly display the chef’s license for their customers to know they can safely eat their food.

21. Fugu is still actually poisonous.

It’s impossible to completely remove the poison from the pufferfish flesh. The chef just removes most of it, with the traces of poison actually giving fugu its unique taste. Even so, it can get dangerous –  so much so that Japanese law forbids the Emperor himself from even eating fugu under any circumstances.

22. The shortest lived fish is the pygmy goby.

A small, coral reef-dwelling fish, a third of an inch long which lives for (at most) 59 days.

23. The longest life span fish is the rougheye rockfish.

A 205-year-old rougheye rockfish was found offshore in the North Pacific.

24. Koi is one of the longest living freshwater fish. 

The oldest living koi was “Hanako,” who died at an age of 226 years in 1977.

25. The longest living commercial fish may be the orange roughy.

The maximum reported age so far has been 149 years.

26. The biggest fish is the great whale shark.

The great whale shark grows to more than 45 feet in length, 23 feet of a girth, and 47,300 pounds in weight. It is larger than the average school bus. However, even larger individual great whale sharks, as long as 61 feet, have been reported. Whale sharks also lay the largest eggs of any animal, measuring 14 inches long.

27. The world’s largest and heaviest bony fish is the ocean sunfish.

The ocean sunfish can weigh up to 2200 lbs and have a length of 12 feet. A female sunfish produces more eggs than any other known vertebrate; it may lay 300,000 eggs at a single spawning.

28. The most poisonous fish in the world is the stonefish.

A master of camouflage, this fish lives off the coast of Australia, on the sea bottoms and around coral reefs, and hides among rocks. It has 13 spikes on its back, all filled with an extremely potent, protein-based, venomous toxin that causes pain, paralysis, and tissue death within a few hours.

Although fatal, stonefish poison is heat sensitive. Heating it causes the poison to break down, losing its deadly properties. This leaves the stonefish’s flesh safe to eat. The stonefish is a very expensive sashimi called okoze, well known as “Deliciously Dangerous.”

29. Seahorses swim upright.

Although they’re the only fish that can swim upright, it takes them over an hour to reach the smallest distances. The speed makes the seahorse look as though they aren’t even swimming at all, just drifting with the ocean currents.

30. Salmon swim for long distances.

Salmon can swim up to 2000 miles in 60 days. They usually swim these distances during mating seasons, when they leave the oceans for inland waters. Once they reach these rivers, they mate and lay their eggs before dying.

31. Schools of fish have a single leader.

Unlike wolf packs, the leader of a school of fish doesn’t stay at the front lines, but in the center of the school. The fish around it follow its direction, swimming in any direction the leader decides to swim in.

32. Most fish can only swim in one direction.

Specifically, fish can only swim forward, which is why you will never see fish swimming backward. If they want or need to go back the way they came, they go around, hence fish sometimes swim in circles. The only exception to this are eels, who do have the ability to swim backwards.

33. Some fish protect other fish from disease.

Scientists call them cleaner fish, and they actually eat parasites or even dead flesh off of other fish’s bodies. Other fish even go to places where plenty of cleaner fish live to have their bodies cleaned.

34. Fish have the ability to make sounds.

Typically, fish rub or grind their bones against each other to produce sounds. Meanwhile, some other types of fish contract or vibrate their swim bladders to communicate with other fish.

35. Daytime fish have very good vision.

Some fish even have better vision than we do; they are able to see ultraviolet light, normally invisible to human beings. On the flip side, nocturnal fish have less developed eyesight, but see better in the dark than we do.

36. Fish have even better hearing.

This is actually an unsurprising fish fact, considering the way sound travels faster in the water than it does in the air. Fish hear with their ears and skeletons, sensing the vibrations of sound in the water. Scientists even suspect that sharks can hear clearly from up to 2 miles away.

37. Fish don’t actually smell bad.

Scientists have discovered that fish don’t normally have the chemicals that our noses pick up as “fishy smells.” Those chemicals are only produced after a fish spends too much time outside of the water. Even then, they must die first before their flesh starts breaking down and producing those chemicals in the process.