Fish: The Ultimate Guide To Fishes & Fish Life (2023)

The ultimate guide to fishes & fish life, including definition of a fish, fish bodies, types of fish and the life-cycle of a fish. Read on for a complete guide to ichthyology…


What Is A Fish?

Fish Ecology

What Are The Main Types Of Fish?

How Many Fish Species Are There?

What Is The Biggest Fish?

What Is The World’s Smallest Fish?

Parts Of A Fish

Do Fish Have Ears?

Do Fish Make Sounds?

How Do Fish Breathe?

Are Fish Cold Blooded?

Fish Life Cycle: Do Fish Lay Eggs?

Fish That Aren’t Fish!

Discover More About Fish With Active Wild

Love fish? See a range of fish gift ideas on this page: Fish Gift Ideas

Fish: The Ultimate Guide To Fishes & Fish Life (1)

What Is A Fish?

A fish is an aquatic vertebrate with fins and gills. The body of a typical fish is streamlined and covered in protective scales. Around half of all known vertebrates are fish, making fish the dominant vertebrate animals on the planet. Fish are found in both salt and freshwater habitats in most parts of the world.

Fish are craniates (i.e., they have skulls), and being vertebrates, have backbones, which are made of bones called vertebrae, through which a spinal cord passes.

Ichthyology is the scientific study of fish, and an ichthyologist is a scientist who studies fish.

Fish or fishes? The word “fish” can be both singular and plural. The word “fishes” can be used instead of the plural form when referring to multiple fish species.

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Fish Ecology

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Fish are found in bodies of water all around the world, and are a vital part of their ecosystems. Fish are heterotrophs* that perform a number of roles in the food chain.

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Depending on the species, fish may either be herbivores (primary consumers), omnivores (secondary consumers) and carnivorous apex predators (tertiary consumers), sitting at the top of the food chain with no predators of their own!

* Heterotrophs are organisms that don’t produce their own food, and therefore have to consume other organisms. Even plant-eating animals are heterotrophs, as they eat plants, which are also organisms.

You can find out more about ecosystems on this page: What Is An Ecosystem?

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What Are The Main Types Of Fish?

You can find out more the different types of fish on this page: Types Of Fish: Examples Of Fish From Around The World

There are three main types of fish: jawless fish, cartilaginous fish, and bony fish.

Jawless Fish (Infraphylum: Agnatha)

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Jawless fish belong to the group Agnatha. As their name suggests, jawless fish lack jaws. Instead, they have round, sucker-like mouths.

There are two types of jawless fish alive today: hagfish and lampreys. Both have long, eel-like bodies.


There are around 80 species of hagfish, all of which are found in the sea. Although they lack true backbones, hagfish have very basic vertebrae, and are therefore considered to be vertebrates.


Around 40 species of lampreys are currently recognized (source). Some lampreys live in freshwater habitats, while others migrate between freshwater and marine environments. Many lampreys are parasites, attaching themselves to the bodies of other fish with their mouths and drinking their blood.

Cartilaginous Fish (Class: Chondrichthyes)

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Cartilaginous fish belong to the class Chondrichthyes. Cartilaginous fish have skeletons made of cartilage – a smooth, flexible tissue – rather than of bone.

Most cartilaginous fish belong to the subclass Elasmobranchii, which is home to sharks, rays and skates.

(The other subclass of Chondrichthyes is Holocephali, which contains fish such as the deep sea ratfish and elephantfish.)


You can find out more about sharks on these pages:
Shark Facts
Types of Sharks

There are around 530 species of sharks. A shark’s skin is covered with placoid scales, which are similar to teeth in their structure; one could almost say that a shark’s skin is covered in teeth. These scales provide protection and also reduce drag and reduces the sound made as the shark swims.

Sharks are equipped with electroreceptors that detect the electrical charges produced by the muscles of other fish. This “sixth sense” is just one of the adaptations that have heled sharks become supreme ocean predators.

Rays and Skates (order: Batoidea)

Rays and skates are fish with flat bodies and which propel themselves through the water by flapping their wing-like pectoral fins. Their mouths gills are located on the underside of the body.

Sting rays are a group of rays whose tails are equipped with a powerful stinging spine.

Electric rays are able to produce an electric charge, which is used both to capture prey and as self-defense against predators. The charge produced by some species is enough to knock a man off his feet, but is not lethal.

The naval weapons torpedoes are named after rays of genus Torpedo.

Bony Fish (Superclass: Osteichthyes)

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By far the biggest group of fish is the bony fish. As the name suggests, the skeletons of bony fish are bone, rather than cartilage.

There are two main types of bony fish: ray-finned fish (class: Actinopterygii) and lobe-finned fish (class: Sarcopterygii).

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Ray-Finned Fish (Class: Actinopterygii)

Nearly all bony fish (in fact, around 99% of all fish) are ray-finned fish. Ray-finned fish have fins that are supported by thin, bony spines. Examples of ray-finned fish include cod, salmon, tuna, pike, piranha, barracuda, minnow and walleye.

Lobe-Finned Fish (Class: Sarcopterygii)

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There are eight living species of lobe-finned fish: six species of lungfish and two coelacanths. Lobe-finned fish have fleshy fins that project from the body on stalks.

At some point around 400 million years ago, the fleshy fins of a group of lobe-finned fish evolved into two pairs of limbs, leading to a new animal group: the tetrapods.

All terrestrial (land-living) vertebrates – including amphibians, reptiles, birds and mammals are tetrapods, and therefore evolved from lobe-finned fish.


Unlike nearly all other types of fish, lungfish are equipped with lungs and breathe air.


Until relatively recently, it was thought that coelacanths had become extinct, along with the dinosaurs, at the end of the Cretaceous Period 66 million years ago. However, in 1938, a coelacanth was caught by a fisherman in South Africa, bringing coelacanths “back from the dead”!

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How Many Fish Species Are There?

There are around 34,300 species of fish, making fish the largest group of vertebrates. Around half of all vertebrate animals are fish!

What Is The Biggest Fish?

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The world’s biggest fish is the whale shark, which has a maximum recorded length of 18.8 m / 61.7 ft.

The second-largest fish is the basking shark, which has a maximum recorded length of 12.27 m / 40.3 ft.

Unlike most sharks, which are active hunters, both the whale shark and the basking shark are filter feeders. Instead of chasing prey, these giant fish swim along with their mouths open and filter plankton from the sea water.

What Is The World’s Smallest Fish?

Several species vie for the title of world’s smallest fish. These include Paedocypris progenetica, an Asian member of the carp family, and the stout infantfish, Schindleria brevipinguis, a marine species found off of the coast of Australia. Both are well under 1 cm / 0.39 inches in length.

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Parts Of A Fish

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Like all animals*, fish require oxygen in order to produce energy. They also need to expel carbon dioxide as a waste product. Most fish perform this process with organs known as gills.

Gills are located behind a fish’s head. The gills of sharks and rays open to the outside of the body; those of other fish are hidden behind bony gill covers called operculum.


Fish scales are small plates that grow from the dermis – the mid-layer of skin. This differentiates them from reptile scales, which grow from the epidermis, the outermost layer of skin.

Fish scales may have their origins in teeth; the scales of sharks contain layers of enamel and dentine, both of which are tissues found in teeth.

The scales of most bony fish (and, therefore most fish) have bony ridges.

Fish Fins

Fish have several different types of fins. Below is a list of the different types of fish fins, and where they are found on a fish’s body. Not all fish have all of these fins.

Dorsal Fin

A fish’s dorsal fin is located on its back. Some fish have two or more dorsal fins, positioned in a line running along the center of the back.

One of the best-known of all fish fins is the dorsal fin of a shark, which is occasionally all that can be seen of the fish as it swims close to the surface of the water.

Pectoral Fins

Pectoral fins are located behind the head near the front of a fish’s body. A fish has a pair of pectoral fins, one on either side of the body.

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The forelimbs of terrestrial animals (including our arms) evolved from pectoral fins.

Pelvic Fins / Ventral Fins

Pelvic, or ventral, fins are located near the base of a fish’s body, one on either side. In most fish they are located further back than the pectoral fins.

The hindlimbs of terrestrial animals (including our legs) evolved from pelvic fins.

Anal Fin / Cloacal Fin

The anal, or cloacal, fin is located behind the anus / cloaca on the base of a fish’s body.

Caudal (Tail) Fin

The caudal, or tail fin, is the fin located at the end of a fish’s tail. In most fish it is used to propel the fish through the water.

Adipose Fin

The adipose fin is a small, fleshy fin found on a fish’s back between the dorsal and caudal fins. It is absent on many types of fish, but can be found on salmon, trout and catfish.

Lateral Line

The lateral line is a line of highly-sensitive cells running along either side of a fish’s body. It is visible on most species of fish. With the lateral line, a fish can sense movement and vibration.

Fish Mouth Types

The shape, size and position of a fish’s mouth is often a good clue as to its diet. There are several different types of fish mouths.

Terminal Mouth

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The most common type of fish mouth is the terminal mouth, which is positioned at the front of the head and which points forwards. Fish with terminal mouths may be carnivores that prey on other fish, or omnivores, capable of eating food from the surface or from the bottom.

Inferior Mouth

An inferior mouth opens downwards, with the upper jaw being longer than the lower jaw. Fish with inferior jaws are usually bottom feeders, feeding on algae, or bottom-living aquatic animals such as crustaceans and shellfish.

Superior Mouth

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A superior mouth opens upwards, with the lower jaw being longer than the upper jaw. Fish with superior mouths are usually ambush predators, waiting for their victims to come within range before striking.

Protrusible Mouth

Many fish have protrusible mouths, which can extend forward to help the fish grab or manipulate food.


Fish don’t have eyelids (the eyelids of many terrestrial animals help keep the eyes moist; something a fish obviously has no need for). Some fish have a nictating membrane, a clear protective cover that is lowered over the eye for protection.

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Do Fish Have Ears?

Fish have ears and are able to hear sound. Fish sense sound with otoliths, dense, bone-like structures in their skulls. With these, the fish is able to detect particle motion in the water. Fish are also able to hear with their lateral lines, and some fish detect sound with their swim bladder, which transmits changes in pressure to the brain.

Do Fish Make Sounds?

Although most fish lack lungs and are unable to make sounds as we do, several fish make sounds with other parts of their bodies in order to communicate. Sounds made by fish include a variety of grunts, croaks and clicks.

Some fish stridulate (produce sound by rubbing parts of the body together) by rubbing their bones or teeth together.

Others produce sound by oscillating the swim bladder.

How Do Fish Breathe?

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Gills consist of threads of tissue known as gill filaments, each of which has many folds (known as lamellae), which increase the surface area.

Running through each filament are thin blood vessels called capillaries. Oxygen in the water enters the fish’s blood, and carbon dioxide is expelled into the water, via these capillaries.

Fish breathe by pulling water into the mouth and expelling it over the gills.

* Only one known animal, a microscopic relative of jellyfish, does not produce energy via aerobic respiration.

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Not all fish breathe with their gills. Lungfish have lungs, which they use either instead of or as well as their gills, coming up to the surface and breathing air.

Gars and the bowfin have “vascularized” swim bladders, which can be used as lungs. This allows the fish to live in poorly-oxygenated water.

Some fish, including mudskippers and some eels, are able to absorb oxygen through their skin, while others, such as catfish, absorb oxygen via their digestive tracts.

Are Fish Cold Blooded?

The majority of fish are cold-blooded (ectothermic), meaning their body temperature is the same as that of their surroundings.

Some fish, including the opah, tuna, the great white shark and other sharks of family Lamnidae, are warm-blooded, with a body temperature higher than that of their surroundings.

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Fish Life Cycle: Do Fish Lay Eggs?

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The majority of fish are oviparous, meaning that the females lay eggs that develop and hatch outside of the body. The eggs of fish are usually fertilized externally by the sperm of the males. Usually, many thousands of eggs are produced, with just a tiny fraction ever reaching adulthood.

Oviparous fish usually hatch in an underdeveloped state, and carry a yolk sac from the egg that provides nutrients until the fish is able to feed itself.

The eggs of oviparous sharks are fertilized internally, with sperm being transferred to the female’s cloaca (an opening on the underside of the body) via an appendage known as a “clasper”, which is located behind the male’s pelvic fins.

Fish may also be ovoviviparous or viviparous.

The eggs of ovoviviparous fish are fertilized internally and hatch within the mother’s body prior to being born.

In viviparous fish, the eggs are fertilized internally, and the developing embryo receives nutrients via an umbilical cord rather than from the egg.

Fish rarely exhibit any kind of parental care; the newly-hatched or newborn fish are usually left on their own!

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Fish That Aren’t Fish

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Several other animals have the word “fish” in their names, but are not true fish. These include starfish, jellyfish, shellfish and cuttlefish.

Cetaceans, a group of marine mammals that includes whales, porpoises and dolphins, are occasionally mistaken for fish. Although cetaceans have steam-lined bodies and fin-like flippers and tails, they are not related to fish (mammals and fish are separated by millions of years of evolution).

Unlike true fish, cetaceans lack gills, and have to regularly come to the surface in order to breathe.

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Discover More About Fish With Active Wild

You can find out more about fish on the following pages:

Types Of Fish: Examples Of Fish From Around The World

Fish Gift Ideas: Fish Themed Gifts For Fish Lovers

Are Sharks Mammals? Is A Shark A Mammal Or A Fish?

(Video) How To Start Fishing - A guide to your first days fishing


What fish need to survive? ›

Water, food and shelter are among the most important requirements: Water: Fish not only live in water, but they get oxygen from water. They breathe by taking water into their mouths and forcing it out through gill passages.

How does the fish find food in its water habitat? ›

Fish rely on their abilities to see, hear, smell, taste and feel to both catch prey and avoid becoming a meal for bigger predators. Food or lure that is alive and moving will be easier for your fish to detect as it has a scent, sound and vibration.

How do fish survive in the water? ›

Many structures in fish are adaptations for their aquatic lifestyle. For example, fish have a stream-lined body that reduces water resistance while swimming. Fish have gills for “breathing” oxygen in water and fins for propelling and steering their body through water.

In what type of environment would you most likely find fish species 1? ›

Fishes live in virtually all aquatic habitats. Different species of fish are adapted for different habitats: rocky shores, coral reefs, kelp forests, rivers and streams, lakes and ponds, under sea ice, the deep sea, and other environments of fresh, salt, and brackish water.

Which fish can live without water for 2 years? ›

But West African lungfish blow these other fish out of the water: They have gills and a primitive lung. During dry periods, the animals wrap themselves in a mucus cocoon, burrow into the mud, and lie dormant—sometimes for years.

What fish can survive without water? ›

African lungfish, Protopterus annectens, can live in suspended animation, called aestivation, without food and water for three to five years. They wake up when water becomes available.

What food makes fish grow faster? ›

After you bring in your new seeds, it is very important to use the Best Quality Feed so that your seeds grow faster, Now the best fish feed in India is CP. CP fish feeds gives the fastest growth and the lowest FCR. It is a premium quality feed and does not pollute the water.

Can fish smell food? ›

Unlike humans who don't smell much underwater, fish actually do have rather good olfactory abilities. Fish use their sense of smell to find food, avoid predators, identify each other, spot safe habitats, and even locate spawning grounds.

Do fish have tongues? ›

Fish tongues however do not resemble the muscular tongues of humans. The tongue of a fish is formed from a fold in the floor of the mouth. In some species of bony fishes the tongue has teeth which help to hold prey items. The name of one genus of argentinid fish, Glossanodon, literally means 'tongue teeth'.

Can fish drown yes or no? ›

Most fish breathe when water moves across their gills. But if the gills are damaged or water cannot move across them, the fish can suffocate. They don't technically drown, because they don't inhale the water, but they do die from a lack of oxygen.

Do the fish get thirsty? ›

As well as getting water through osmosis, saltwater fish need to purposefully drink water in order to get enough into their systems. Where their freshwater counterparts direct all of the water that comes into their mouths out through their gills, saltwater fish direct some into their digestive tract.

Do fish know they live in water? ›

Have you ever thought that you might be immersed in an environment and not know it? Like fish are unaware of being in water, many Christians are just as unaware of the postmodern world they live in and the influence it has on their lives.

Which fish can live in both freshwater and saltwater? ›

Fish that can tolerate a wide range of salinity at some phase in their life-cycle are called euryhaline species. These fish, which include salmon, eels, red drum, striped bass and flounder, can live or survive in wide ranges of salinity, varying from fresh to brackish to marine waters.

Why saltwater fish can't live in freshwater? ›

All fish need an element of salt in the water. Koi carp need between 0.13 and 0.23% of salt in the water. The salt is drawn into their system via osmosis and keep the balance. If salt or freshwater fish are in the wrong water, salt will be drawn in or out of the body and kill the fish.

Where do fish sleep? ›

While fish do not sleep in the same way that land mammals sleep, most fish do rest. Research shows that fish may reduce their activity and metabolism while remaining alert to danger. Some fish float in place, some wedge themselves into a secure spot in the mud or coral, and some even locate a suitable nest.

Can fish feel pain? ›

Fish do feel pain. It's likely different from what humans feel, but it is still a kind of pain.” At the anatomical level, fish have neurons known as nociceptors, which detect potential harm, such as high temperatures, intense pressure, and caustic chemicals.

Is there an animal that can breathe air and water? ›

Amphibians are vertebrates (animals with backbones) which are able, when adult, to live both in water and on land. Unlike fish, they can breathe atmospheric oxygen through lungs, and they differ from reptiles in that they have soft, moist, usually scale-less skin, and have to breed in water.

What animal survives 10 days without water? ›

Camels can survive up to 15 days without water. One of the reasons that they can survive that long is because of their humps. They store fat in their humps (not water) and can use this to help them go longer without water.

Can fish survive the toilet? ›

As experts were quick to point out following the movie's release, flushed fish typically die long before they reach the ocean, going into shock upon immersion in the toilet's cold water, succumbing to the noxious chemicals found in the sewage system, or—if they make it this far—finding themselves eliminated at a water ...

Which fish has the loudest sound? ›

Now—thanks to new research by Brad Erisman at the University of Texas at Austin's Marine Science Institute and his colleagues published in the journal Biology Letters—we know that the Gulf corvina are the loudest known fish on the planet.

Is there a fish that hates water? ›

“These Pacific Leaping Blenny seem afraid of the waves. They are poor swimmers and would be easy prey in the sea.” Instead of finding food in the water, the blenny feeds on algae which grows on the cliff face. To avoid being swept off the rocks, the little fish can leap far further than its three inches of body length.

What stops fish from growing? ›

Fish growth can be disrupted through many factors, but pollution of the water via biological waste products is the main reason for stunted growth.

Do fish grow faster in warm water? ›

Our results show that fish do grow faster in warmer waters, but much less than is typically predicted by the Metabolic Theory of Ecology and used in modelling studies that predict climate change impacts.

What food attracts fish? ›

Looks like fried chicken and ghee rice are the favourite 'dishes' of freshwater fishes as well. The fishermen and anglers say that they use chicken fry and ghee rice as bait to catch freshwater fishes. Earlier the anglers attached earth worms or prawns as bait on fishing hooks to attract fish.

Do fish have feelings? ›

Nerves, brain structure, brain chemistry and behaviour – all evidence indicates that, to varying degrees, fish can feel pain, fear and psychological stress.

Can fish see in the dark? ›

Fish living in the deep sea manage to navigate in complete darkness. It's not strictly 'seeing' but fish have rows of pressure-sensitive organs running down each side of their body called the lateral line, which allows them to sense nearby animals from the pressure changes in the water.

Do fish have balls? ›

Most male fish have two testes of similar size. In the case of sharks, the testes on the right side is usually larger.

Do fishes cry? ›

The cerebral cortex and limbic system are absent in fish. Cerebral cortex, which is what permits other animals to cry.

Can fish hear humans talk? ›

Yes, fish can hear you talk!

Sounds that are created above water typically do not carry enough force to penetrate the surface tension of the water, so talking on the boat or loud noise may not affect fish as much as your fellow anglers may want you to think. Your voice is unlikely to spook or scare fish away.

Can a fish drown in milk? ›

The differences in acidity and dissolved oxygen, not to mention all of the fat, proteins, carbohydrates, and other minerals in the milk that might clog the creature's gills, would quickly spell trouble. The animal would likely die within minutes, if not sooner.

Can a fish get scared to death? ›

What is this? Stress! It isn't good for humans, and it definitely isn't good for fish. Stress on fish eventually result in its death.

Can fish drown in ice? ›

They survive just fine under the ice,” says Jake Vander Zanden, Director of the University of Wisconsin–Madison Center for Limnology. “They are adapted to survive in these low temperatures; it's not that big of a deal.”

Do fish feel pain when hooked? ›

The wild wriggling and squirming fish do when they're hooked and pulled from the water during catch-and-release fishing isn't just an automatic response—it's a conscious reaction to the pain they feel when a hook pierces their lips, jaws, or body.

Do fish get lonely? ›

In captivity, it's strongly recommended that they should be kept at least in pairs, to provide companionship. If you watch fish in a tank, you'll see that they regularly engage with other fish. It's thought that solitary fish, much like solitary humans, may begin to suffer from depression and lethargy.

Can fish see humans? ›

Researchers studying archerfish found the fish can tell a familiar human face from dozens of new faces with surprising accuracy. This is a big, big deal. It's the first time fish have demonstrated this ability.

Do fish know we are human? ›

A species of tropical fish has been shown to be able to distinguish between human faces.

Do fish survive after being hooked? ›

Controlled studies have shown that most fish released after hook-and-line capture, survive.

Which animal can live both in water? ›

Amphibians can live on both land and water. Amphibians like to live near water bodies. Amphibians can breathe on land as well as in water. Frogs, salamanders and toads are some examples of amphibians.

What is the largest fish in the ocean? ›

The biggest fish in the ocean is the Rhincodon typus or whale shark. Despite their tremendous size and intimidating appearance, whale sharks are commonly docile and approachable. Please keep your distance, giving them the respect and space they deserve.

Why do marine fish burst when thrown under tap water? ›

Due to unequal osmotic concentrations, osmosis (endosmosis) occurs and because of this water gets into the fishes' body till the concentration (inside fish) becomes isotonic to that of tap water. Due to this, the fish start to swell, a stage comes when the fishes' body bursts and they die.

What happens if you put a saltwater fish in regular water? ›

A fish that lives in salt water will have somewhat salty water inside itself. Put it in the freshwater, and the freshwater will, through osmosis, enter the fish, causing its cells to swell, and the fish will die.

Does fish urinate? ›

Fish have kidneys which produce urine containing ammonium, phosphorus, urea, and nitrous waste. The expelled urine encourages plant growth on coral reefs; downstream benefits also include increased fertilization of algae and seagrass, which in turn provides food for the fish.

What do fish do all day? ›

Each fish gets food especially for them – some eat plankton and fruit flies, others eat seeds and vegetables; some fish hunt for their food, others forage for it. Once they've eaten, fish spend their days guarding their homes, and at this time of year, breeding season, they spend lots of time competing for mates.

Do fish have teeth? ›

Fish Teeth Exist

All fish have teeth. Specific types of swimmers—like goldfish—hide their pearly whites near the back of their throats. Similar to shark teeth, goldfish lose and replace teeth throughout their lifetime.

What are the 4 things fish need to survive? ›

Food, water, filtration and heat are the basic elements you'll need to provide for your pet fish, but the exact specifications will depend on the type of fish you choose, how big it grows and a number of other factors.

What do fish need list? ›

Your fish need the following to survive:
  • A balanced diet.
  • Clean water.
  • Appropriate light.
  • A proper filtration system.
  • Water conditioner to balance pH levels.
Jul 1, 2021

What is the easiest fish to keep alive? ›

Some of the easiest fish to take care of include white cloud minnows, cherry barbs, goldfish, guppies, neon tetras, and cory catfish. All of these species are relatively peaceful, non-demanding fish that do well in a beginning fish tank.

What nutrients do fish need to survive? ›

The key minerals fish need in bulk are calcium and phosphorus. Calcium is found in hard water and can be absorbed through the gills, and phosphorus is found in live underwater plants. Fish also need trace amounts of iron, iodine, magnesium, sodium, chloride, potassium, sulfur, copper, and zinc.

Do fish have 4 hearts? ›

Fish hearts have just two chambers, an atrium and a ventricle (Figure 1). Insects often have just a tube that pumps hemolymph (the name for the insect equivalent of blood) freely around the entire body, with a vessel to help it move. Cockroaches, however, have 13 heart chambers!

How often do you have to clean a fish tank? ›

Depending on how many fish you have, and how messy they are, most tanks require cleaning about once every two weeks. Cleaning should involve: ✔ Siphoning the gravel to remove any debris and uneaten food, and changing about 10-15% of the water.

Do fishes drink water? ›

As well as getting water through osmosis, saltwater fish need to purposefully drink water in order to get enough into their systems. Where their freshwater counterparts direct all of the water that comes into their mouths out through their gills, saltwater fish direct some into their digestive tract.

Do fish get bored in a tank? ›

Fish-keepers sometimes see their pets 'glass surfing' – swimming repeatedly up and down the glass of the tank. This could be the aquatic equivalent of the pacing of a captive tiger that's bored from a lack of stimulation. But the fish could also be stressed from an overcrowded or unfamiliar tank.

What are the five importance of fish? ›

Fish is filled with omega-3 fatty acids and vitamins such as D and B2 (riboflavin). Fish is rich in calcium and phosphorus and a great source of minerals, such as iron, zinc, iodine, magnesium, and potassium. The American Heart Association recommends eating fish at least two times per week as part of a healthy diet.

What are the 3 important source of fish? ›

Fish is a good source of high-quality protein, vitamin D and omega-3 fatty acids.

What fish dies if it stops moving? ›

Instead, these sharks rely on obligate ram ventilation, a way of breathing that requires sharks to swim with their mouths open. The faster they swim, the more water is pushed through their gills. If they stop swimming, they stop receiving oxygen. They move or die.

Which fish loves longest? ›

Bigmouth buffalo can live to 112—the oldest confirmed freshwater fish. This bigmouth buffalo (Ictiobus cyprinellus) was photographed at Gavins Point National Fish Hatchery and Aquarium, in South Dakota. Carbon dating has validated that the species is the longest-lived freshwater fish known.

What is the healthiest food for fish? ›

The protein source must contain all essential amino acids for the fish to live. The best source of these for fish is animal protein, specifically fish meal. Fish meal is any leftover fish scraps from processing fish into other products, mostly for human and cat consumption.

Which vitamin is best for fish? ›

The Importance of Vitamins for Fish in Aquariums
  • Vitamin A - from greens and crustaceans. ...
  • Vitamin B - Complex - from greens, eggs, and fish. ...
  • Vitamin C - from greens, algae, and fish eggs. ...
  • Vitamin D - from snails, shrimps, and earthworms. ...
  • Vitamin K - from water fleas, greens, and liver.


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Author: Manual Maggio

Last Updated: 04/09/2023

Views: 6400

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Author information

Name: Manual Maggio

Birthday: 1998-01-20

Address: 359 Kelvin Stream, Lake Eldonview, MT 33517-1242

Phone: +577037762465

Job: Product Hospitality Supervisor

Hobby: Gardening, Web surfing, Video gaming, Amateur radio, Flag Football, Reading, Table tennis

Introduction: My name is Manual Maggio, I am a thankful, tender, adventurous, delightful, fantastic, proud, graceful person who loves writing and wants to share my knowledge and understanding with you.