With a mouthful of these pearly whites, it’s not hard to see how the wolf fish got its name.  Don’t worry, though.  While those wicked fangs may look like they’re made for tearing flesh, the Atlantic wolf fish feeds exclusively on mollusks, crustaceans, and echinoderms (snails, crabs, and sea urchins, for those wondering).  

Atlantic wolf fish also make really good parents.  Unlike most fish, which lay their eggs and hope for the best, these wolf fish work together as a couple.  Both the male and female guard the eggs (which are some of the largest fish eggs in the world, and therefore irresistible to predators) and, when they hatch, the parents take care of their newborn young until they are strong enough to fend for themselves (this can take up to four months in some cases).  Bringing new Atlantic wolf fish into the world is a pretty important job (wolf fish do an excellent job of eradicating invasive invertebrates), and these parents take pride in their work.

As the name implies, the Atlantic wolf fish lives in the Atlantic Ocean.  It isn’t a very good swimmer, so the wolf fish make its home in various nooks and crannies found on the seafloor, which also happens to be where its prey lives.  Sounds like a pretty sweet setup, right?  Wrong. At the bottom of the ocean, it gets cold.  Like below freezing cold.  The sea water isn’t affected because it contains salt, which lowers the freezing point of water, but blood is a different matter.  In order to survive, the Atlantic wolf fish has developed a natural antifreeze that runs through its veins and keeps things running smoothly. That is one cool fish.

Although they may not look like it, eels are a fish, and fish aren’t known for their intelligence.  The giant moray eel, however, is one of the few exceptions.

Commonly found in the Indo-Pacific region of the oceans, the giant moray lives in coral reefs, sleeping in the many crevices of the reef during the day, coming out at night to hunt fish and crabs.  While it isn’t the longest eel in the moray family (slender giant morays can get up to 13 feet long, versus the 10 feet of the regular giant moray), it is considered the largest, since it is considerably heavier, tipping the scales at 66 pounds.  The giant moray also has a secondary set of jaws (pharyngeal jaws for the scientifically inclined) that operate independently from the primary jaws to drag food down towards their stomach.

Giant morays can be fierce creatures, attacking anything that invades their personal space, in some cases, causing scuba divers to lose fingers, or even entire hands.  However, morays have been known to form lasting friendships with divers, and in one case, an eel recognized and played with a diver that had not been in the area for three years.

That isn’t the only clue to the morays intelligence.  The giant moray is the only known fish to participate in interspecies cooperative hunting (along with its partner, the roving coral grouper).  The grouper will invite the giant moray to hunt, and the moray obliges, flushing out small fish in the parts of the reef that the grouper can’t reach.  In return, the moray gets to keep the fish that the groupers don’t catch, showing just how extraordinary the giant moray eel is.

Eelpouts (family Zoarcidae) are a type of fish that get their names from their elongated bodies and perpetual frowns.  The pink vent fish is a member of this family, but its name comes from something other than looks.  A very loose translation of the genus Thermarces is ‘keeping close to heat’, which true, because this fish pretty much only lives around hydrothermal vents.  These vents are caused by cracks in the ocean floor that release superheated water (around 600 degrees Fahrenheit) and minerals that create oasis where life can thrive among the otherwise barren abyssal plain.

Pink vent fish have made themselves right at home in this inhospitable environment.  The hydrothermal vent’s warm water and abundance of minerals makes it into a literal hot spot for bacteria, which attracts copepods and amphipods, snails, giant tube worms, crabs, octopuses, and fish.  The pink vent fish is at the top of the food chain here, but prefers to go after the smallest prey.  While it mostly eats the tiny limpets that attach themselves to the tube worms, this fish will also eat amphipods, copepods, and the occasional snail.

We really don’t know that much about the pink vent fish.  Their size, lifespan, behavior, and reproduction is still a mystery. That’s because the water 7,500 feet down is under a tremendous amount of pressure; more than 220 times greater than the pressure at sea level.  That means that the pink vent fish is swimming through waters that have a pressure of 3,250 pounds per square inch.  This fish can survive down there because it’s had millions of years to adapt to this environment, while humans only discovered the vents that they live on in 1949, and didn’t develop technology to explore them until 1964.  But who knows?  Maybe, in the near future, we’ll devote more resources towards learning about this elusive deep sea creature, and eventually all other creatures of the ocean as well.    

The ocean sunfish is a big fish.  While its average weight of one metric ton (that’s a little more than a short ton and a little less than a long ton) seems positively miniscule compared to the bulk of the whale shark (up to 66,000 lbs), it is the heaviest bony fish in the world.  It also happens to hold the record for the most eggs produced at once by any vertebrate; 3 million.  While these two things may or may not be related, the truth is that the ocean sunfish is a very unusual animal.

First of all, ocean sunfish don’t swim like other fish do.  Their caudal fin (that’s what most fish use to propel themselves through the water) has completely disappeared, leaving behind a flap of skin that is used as a rudder.  In order to move, the anal fin and dorsal fin have become enlarged (they’re as tall as this fish is long- about 10 feet) and are waved side to side to move the ocean sunfish forward.  Since this method of locomotion would cause trouble if this fish were wide, the ocean sunfish has evolved to be thin and streamlined.

Then there is the diet. Ocean sunfish eat jellyfish.  A lot of jellyfish.  Since jellyfish are 95% water, this doesn’t make a very nutritious meal for the ocean sunfish, which is why it has to eat so much. Luckily for this fish, jellyfish don’t swim that fast, and don’t even need to be chewed, which is good, because the jaws of the ocean sunfish can’t close all the way.  All it has to do is get near the senseless cnidarian and suck it in.

This seems like a pretty easy life, doesn’t it?  Well, the ocean sunfish does have problems, and those problems take the form of parasites. Since it’s so big and flat, this fish makes an excellent host for anything that wants to live on its skin. The ocean sunfish is constantly seeking out ways to relieve itself of these nasty biters.  Sometimes it goes to cleaner stations, places where smaller fish will pick the parasites off and eat them, other times it jumps out of the water (up to 10 feet vertically) to try to dislodge them.  The most famous, though, is what they do just below the surface. Ocean sunfish will float, one side out of the water, one side still submerged, allowing gulls and other seabirds to land on it and eat any parasite that they can find.  Then, once one side is cleaned, it will roll over, and let the birds work at the other side.  

Come one, come all, to see the world’s rarest fish!  Does it live in the darkest trenches of the ocean?  A remote lake hidden by the greenery of a dense jungle?  Perhaps it is locked away by an aquarium enthusiast who would rather die than let others set eyes on their precious pisces.

The answer is actually none of the above.  Meet the Devil’s Hole pupfish, one of the 120 or so species of pupfish that are found across the globe.  

This one stands out, not because it is extremely isolated (many species of pupfish are located in isolated pools of water), not because it is found in a desert (pupfish thrive in small oases), not even because the desert it lives in happens to be in Death Valley (there are actually five species of pupfish that live there).  

The Devil’s Hole pupfish is special because there are so few of them.  Living in one of the smallest ranges of any vertebrate, the last count of this tiny fish put its population between 35 and 65.  Devil’s Hole is a geothermal pool found in a cave in the mountains of Death Valley.  The pool is about 400 feet deep, has an opening at the surface that is 6 by 18 feet, and maintains a constant temperature of 92°F.  

This habitat would be lethal to most other fish, not only because of the high temperatures, but because the water also has an extremely low oxygen content.  The Devil’s Hole pupfish have been adapting to this environment for thousands of years, and are considered a valuable scientific resource by many.

Because this fish is almost extinct, there have been many attempts at conservation.  Divers go in every year to check the population, and at the nearby Ash Meadows Fish Conservation Facility a new home is being made to combat the Devil’s Hole pupfish’s shrinking habitat.

With the largest of its kind ever recorded reaching a length of 24 feet, the beluga sturgeon is the biggest of all sturgeons.  It is also the largest anadromous (living in saltwater but moving to freshwater to breed) fish in the world.  

The beluga sturgeon is usually found in the Caspian Sea, as well as the rivers of Russia.  Despite sharing the same name with the beluga whale, the beluga sturgeon is not related at all, but both names are derived from the same source; the Russian word for ‘white’.

The eggs of the beluga sturgeon, commonly called caviar, are among the most expensive in the world, costing about $4,500 per pound.  Because their caviar is such a delicacy, beluga sturgeons are being fished at a rapid rate, which is unfortunate for them, since it cuts their lifespan so short- the oldest known beluga sturgeon lived to be 118 years old.

The coelacanth is a special fish.  When one was pulled up by a trawler near the Chalumna River in 1938, the captain, who had never seen a fish like it before, called his friend Marjorie Courtenay-Latimer (the curator of a nearby museum) to see if she could identify it. Marjorie couldn’t find anything like it in any of her books, so she called her friend James Leonard Brierley Smith. As soon as he saw it, he recognized it as a coelacanth.

You may wonder what is so special about this large lobe-finned fish.  Well, the coelacanth is a living fossil.  It is one of the few surviving tetrapodomorphs (a sort of missing link between walking and swimming creatures), lived during the time of the dinosaurs, and was thought to have gone extinct with them, 65 million years ago, until it was rediscovered, virtually unchanged.

There are two species of coelacanth living today.  The Indonesian coelacanth is found near Indonesia, is usually around 4 feet long, and is brown.  The West Indian Ocean coelacanth lives off the coast of east Africa, can reach more than 6 feet long, is blue, and is critically endangered.

Imagine swimming in the warm waters off of Australia’s southern coast.  You see a lone clump of seaweed drifting about, and move closer to investigate.  Then you notice something strange; this piece of seaweed has eyes.  That’s because that seaweed is actually a leafy seadragon, a fish related to seahorses and pipefish.

The leafy seadragon is usually between 8 and 10 inches long and is covered in leaf-like protrusions that help to hide this fish from predators.  Not being seen is important to leafy seadragons, because they have absolutely nothing to defend themselves with and are poor swimmers, using their small pectoral fins (the ones on the side of their head) to steer them through the water.  

The leafy seadragon’s camouflague also comes in handy when they catch prey.  Since they can’t swim fast to chase after things, these fish let their food come to them.  Disguised as a piece of seaweed, the leafy seadragon slowly floats around spots where the small crustaceans and plankton that it eats are found.  When their prey gets close enough, it simply sucks them into its long, tube-like mouth before the unfortunate invertebrates realize that the seaweed was actually an animal.

Like their cousin the seahorse, it’s the males of this species that raise the kids.  After mating, the female leafy seadragon will lay her eggs on a special spot on the male’s tale called a brood patch, which supplies the eggs with oxygen.  After about nine weeks, the eggs are ready to hatch, so the male helps them by shaking his tail to dislodge the eggs.  

The whale shark is the world’s largest living fish.  The biggest one ever measured was over 40 feet long and weighed more than 20 tons. Despite all of this, whale sharks are harmless.  They’re filter feeders, one of three species of shark that subsist entirely on plankton.

As I said before, whale sharks are harmless.  They’re very docile; divers can pet them, and even hitch a ride on their backs (although that is frowned upon by conservationists).  There have even been reports of juvenile whale sharks playing with divers.  They do have teeth (about three thousand of them), but they aren’t used at all and are extremely small, like the size of the letters on a keyboard small.    

Whale sharks can be found in warm waters worldwide.  They usually spend their time in the open ocean, but sometimes swim into lagoons and atolls, possibly for breeding purposes.  Every spring, hundreds of whale sharks migrate to the coasts of Australia, where the spawning of the Ningaloo Reef allows them to gorge themselves on coral spawn.

What if I told you that there is an animal that can be found in Europe, Asia, and the Americas, is carnivorous, has 15 sets of legs, and is probably IN YOUR HOUSE RIGHT NOW AND IT LOOKS LIKE THIS!!

Although it may look like some sort of alien monster, it’s actually the humble house centipede. They’re relatively harmless (most of these arthropods couldn’t hurt you if they tried due to their tiny teeth) and eat the bugs you should really be worrying about (aka cockroaches, termites, silverfish, and bedbugs).  House centipedes don’t carry disease, don’t destroy your property, and try to stay out of people’s way.  

The body of a house centipede is only about an inch long, but thanks to those ridiculously long legs and antennae, it can look much bigger.  It also spends a significant amount of time keeping those legs clean. Like a cat, it will groom itself, meticulously making sure that everything is in proper order.  So next time you see one of these centipedes crawling out of your drain, try not to scream or panic, and remember that this is one bug that you don’t want to squish.