What Is a Fish?


A fish is a vertebrate, an pet with a backbone, i m sorry has adjusted to life in the water. Every fish:

have a backbonebreathe oxygen, in ~ least component time, utilizing gillsare safeguarded by scaleshave a basic hearthave a centralized body and use fins for swimming

What other pets are vertebrates? Mammals (such as cats, horses, and elephants), reptiles (such together snakes and also lizards), amphibians (such as toads and also frogs), and birds likewise have a backbone.

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Not all underwater animals are fish. Whales and also dolphins space mammals. A mammal is a vertebrate the produces milk to feed your young.

Jellyfish, starfish, and octopus are marine invertebrates - pets without backbones.

How carry out Fish Breathe?


All animals need oxygen come survive. Fish have special organs dubbed gills. Gills are situated on the sides of a fish"s head. They space made of thin sheets or membranes.

After fish open their mouths and take in water, lock pump it come gills. Fish absorb liquified oxygen as water passes through gill membranes. Once oxygen is absorbed, water flows out v the gill openings.

How countless Kinds the Fish room There?


Fish have actually been on earth for an ext than 500 million years. There were fish in the water even prior to dinosaurs roamed the earth! Today, there are three main varieties of fishes:

Bony fishes, favor tuna, eels, and trout

There room over 30,000 different types of fish in the world. That"s more than every the amphibians, reptiles, birds, and also mammals combined! Every year, 200 come 300 brand-new fishes are discovered and named. That is approximated that there might be as numerous as 15,000 fish types yet to be identified. Fish scientists, called ichthyologists, regularly reclassify fish as different species as they learn an ext about them.

Fish come in all shapes and also sizes. The the smallest fish is the stout infantfish, measuring about 1/4 that an customs (8 mm) lengthy when completely grown. Whale sharks can prosper to 42 ft (16 m) in length. The most difficult bony fish is the ocean sunfish, which can weigh as much as 5,000 pounds. One adult white sturgeon, the largest freshwater fish in north American, can weigh an ext than 400 pounds, reach an ext than 12 feet in length, and live over 100 years.

When it pertains to shape, in basic fish are systematized with a spicy anterior (snout), a pointed posterior (rear), and also a broad propulsive tail. This torpedo-shaped human body is typical of the fastest-swimming fishes. Streamlined method that it is an reliable shape because that speeding through the water. Airplanes have actually a similar streamlined form for moving through air. However not every fish have the very same shape! Rays have flat, triangle bodies, when inflated puffer fish room round favor spiky balloons, and also eels look much more like snakes. Fish room a really diverse team of animals!


Where have the right to Fish be Found?


Fish can be found in almost every kind of water habitat. They can live high up in mountain streams, in warm desert springs, in drying mud, in topical ponds, and deep in the ocean. Some fish grow in warmth waters, if others need cold water come live. The Antarctic icefish have the right to survive in water listed below 0° C (32° F) due to the fact that their blood contains special chemicals that keep their bodies from freezing.

Some fish, such together trout and also catfish, live in freshwater, which has lakes, rivers, ponds and also streams. Various other fish, choose tuna and also cod, live in the saltwater the the oceans, coral reefs, and also bays. And some live in both! Read about one of Idaho"s unique fish, the salmon, i m sorry live component of your life in freshwater and part in saltwater.

What execute Fish Eat?


The diet the a fish counts on what form it is. Part fish space herbivores that eat aquatic plants and also algae. Others are carnivores, that eat other fish, insects, crabs, frogs, snakes, and even ink or octopus. Part sharks space predators who hunt for prey. Countless fish space omnivores, feeding ~ above both plants and also animal life.

Fish and also Humans


Fish are vital to human being for numerous reasons. They space a resource of food everywhere the world. For some people, fishing is their job and the method they support themselves, while for others, fishing is a funny hobby. Some people keep fish as pets, and also others favor to excellent beautiful fish if underwater or at zoos or aquariums.


Fish are critical part of the food chain everywhere the earth. Whatever that affect the ecology of ours planet eventually affects humans too, so maintaining fish populaces is important. It is estimated that around 1,000 species of fish are at this time in peril of extinction. Part fish species are threatened as result of human activity. Human being sometimes overfish specific populations that fish, such as cod and also tuna. Overfishing hurts the entire species because the continuing to be fish can"t give birth fast enough to preserve the population. One more threat come fish is your habitat being destroyed. Fish that count on coral reefs can become threatened once the reefs space destroyed, and also fish living in rivers have the right to be endangered if a dam is built or water is polluted. Fish that call for shade and also cold water will experience if logging gets rid of trees and also water i do not care warmer.

Fish Facts

Fish Lifespans

The Coral Reef Pygmy Goby lives only 5-6 weeks, while the Greenland Sharks have an average lifespan of 272 years! Scientists recognize a fish"s period in lot the same method they figure out the period of a tree. Favor a tree, fish are constantly producing brand-new layers of growth. Scientists look at growth rings on a fish"s scale and/or the ringlike structures found in a fish"s otoliths (small skeleton of the within ear). Throughout times of slow-moving growth, the great of development in these locations are closer together and also darker. In the summer once fish room growing an ext quickly, this layers of growth are spread out, causing a lighter area.

Fish Scales


Overlapping scales aid to safeguard fish native injuries and attacks native predators. Scales also aid reduce water resistance when the fish is swimming. Often, fish scales room covered with a great of slime which helps the fish move more quickly v the water. Over there are four kinds the scales. Go to the Australian Museum to learn more about the different species of fish scales and see photos.


Fish Defense

Fish protect themselves indigenous predators by swimming with each other in huge groups dubbed schools. Another means that many fish protect themselves is to usage camouflage to blend in with their environment. Fish will certainly adapt their colors to enhance the sand, and also some also have scales the look choose plants uncovered in coral reefs. Some flatfish usage camouflage to make themselves look favor a rock on the s floor.

Fish Senses

Fish are believed to have actually a good sense the sight, touch, and taste. They additionally have a specialized sense organ called the lateral line which is comparable to radar, helping them navigate and find their way in dark or muddy water.


Fossil fish

The Coelacanth is a life fossil that has changed tiny in that 400 million year on Earth. This ancient fish provides scientists a home window into what the earth was favor a long time ago. Don"t miss out on the story the this fascinating varieties and various other fossil fish.

Strange Fish

Almost all fish attain oxygen through their gills underwater, however a few, such as the lungfish, deserve to breathe wait on land. Virtually all fish place eggs, yet a few, such as sharks, provide birth come live young. Practically all fish need to remain in the water at every times, however the mudskipper have the right to use its fin to walk on land. Seahorses room the just fish that swim in an upright position."Cleaner fish" aid other fish by remove parasites and dead skin from their scales. Flying fish propel themselves the end of the water at speeds of 37 mph, reach heights of end 4 feet and glide distances of up to 700 feet.

Idaho"s native Fish Species

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Of every the thousands of different kinds of fish in the world, only about 100 species are uncovered in Idaho. And of those 100, only 39 to be originally native to Idaho and not carried in from somewhere else.

Some the Idaho"s best-known native species are cutthroat trout — the Idaho State Fish — and also rainbow trout, bull trout, steelhead trout, chinook salmon, kokanee salmon, sockeye salmon, whitefish, and also white sturgeon.

What Is a aboriginal Species?


We say pets are aboriginal if their varieties has stayed in the same ar for a very long time. For example, cutthroat trout have remained in Idaho for over one million years, for this reason they are absolutely native to Idaho. There room 39 types of fish the are aboriginal to Idaho.

Native pets are crucial parts that the environment. They all do necessary jobs, or fill niches, in their habitat. Because that example, deer have an essential job. They are nature"s lawn mowers.

Can friend think the a project that among Idaho"s aboriginal fish does? Read about salmon"s job.


Check the end the Idaho Fish and Game Department"s game Fish identification site, v photos, descriptions, life histories, feeding habits and also angling techniques.

Where Do native Fish Live?


Most that our native fish live in cold, clean water. Cold water is various from warmth water. Cold water deserve to retain an ext oxygen than heat water. Every fish require oxygen come breathe, similar to you do, yet they gain it native the water. Oxygen in water is called dissolved oxygen. Cold water deserve to hold a most oxygen, so fish the live in cold water habitats usually have actually no problem getting every the oxygen they need. Cold water is also usually a little cleaner and also clearer.

Trout favor clear water, but they don"t favor to see their neighbors. Trout deserve to live pretty close to every other. They simply need sufficient food and also a “wall” between themselves and also other fish. Please logs or rocks make nice “walls” between neighbors. Great cold water habitats require fallen logs, rocks or various other plants to give fish hiding places. Usually cold water is moving. The Boise River, Salmon River and also Selway flow are examples of cold water habitats in Idaho.

It"s necessary to save our water clear and clean. Learn all around the importance of healthy streams for fish.

Check out whereby other indigenous Idaho fish live and what a riffle is!

Are all of the Fish in Idaho Native?


Not anymore. A long time ago, every one of the fish in Idaho to be native. But when settlers relocated here, they brought non-native species to our state, such together brook trout, brown trout, catfish, crappie and blue gill.

If you moved to Idaho from one more state or country, you are a “non-native.” Sometimes, a plant or animal types can be a non-native too! human being have relocated both plants and also animals to Idaho, sometimes on purpose and sometimes by mistake.

Why Did human being Introduce Non-Native Fish in Idaho?

Most non-native fish were introduced right into Idaho top top purpose since people liked to capture them. When the inhabitants moved right here they were supplied to catching certain fish, favor brook trout and also catfish.

When they arrived in Idaho, those species of fish weren"t here. Rather of transforming what kind of fish castle caught, the settlers made decision to bring their favourite fish here. They permit them walk in Idaho"s rivers and lakes, and also now those non-native fish live here and also reproduce on your own.

Where perform Non-Native Fish Live?


Many, but not all, of the non-native fish in Idaho like heat water habitats prefer shallow ponds and reservoirs. Warmth water usually has less oxygen in it. The warmer the water gets the harder that is because that water to organize onto oxygen. Warm water usually has fish life in it the have interesting ways to gain the oxygen lock need.

Catfish, called brown bullheads, room a species of non-native fish that you can uncover living in heat water. Bullheads have the right to breathe v their skin. Lock can even use your air bladders as an emergency lung by coming up to the surface of the water and also gulping air. They host the air in their air bladders climate “burp” the waiting out. The air can pass over their gills, so they can acquire oxygen out of the air. Quite amazing!

Warm water is generally murky. This is where the catfish"s whiskers come in handy. Their whiskers help them uncover their means around and also “smell” the water because that food. Water warmth is usually still.

Non-native fish live in cold water, too. Part non-native fish like to live in cold, clean streams and lakes. Our aboriginal fish favor the exact same habitats. Typically one types of fish wins, or out-competes, the other types of fish because that habitat.

Cutthroat Trout

US Fish & Wildlife Service

Cutthroat trout space Idaho"s state fish! castle are found from the Rocky mountains west come the Pacific Ocean and from Alaska south to brand-new Mexico. Cutthroat might live in small mountain streams, large rivers choose the snake River, or large desert lakes. There are also cutthroat trout the spend part of their lives in the ocean!

Some cutthroats live in really cold places like Stanley, Idaho while other cutthroats live in hot deserts. There are cutthroat trout that never gain larger that six inches long. Other cutthroats may weigh more than 40 pounds. There room silvery cutthroat, golden cutthroat and cutthroat the look choose rainbow trout. Some cutthroat have huge spots; some have tiny spots. Still rather have almost no spots at all.

There are at least 14 subspecies, or types, of cutthroat trout life on the planet. But no issue what their names, shapes, sizes, color or lifestyles, cutthroat all have actually one point in common: the glowing red slash marks under your throats, i beg your pardon is just how they got the surname cutthroat.

Native Fish Have necessary Jobs


Salmon room fertilizer. Salmon swim every the method to the ocean and also then earlier to Idaho"s streams, wherein they spawn, or lay their eggs. Lock die an extremely soon ~ spawning, and also their decaying body fertilize ours rivers, streams, lakes and forests.

Microorganisms, tiny little animals, help decompose salmon flesh. These tiny pets then become food for small fish, also baby salmon. These small fish then become food for birds and other fish. When pets like bears and otters traction salmon right into the woods come eat them, they room bringing nutrients into our forests. Find why fish need trees and why trees need fish.

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Salmon are the only method to relocate nutrients native the ocean back to our ecosystems in Idaho. Every day, everyday, Idaho"s rivers room carrying nutrient to the ocean. Without salmon, it would certainly be a one-way expedition for these necessary elements.