what is a fish? characteristics, features, examples of the animals with fins, gills, and scales...

What is a Fish?

Characteristics, features, examples of the animals with fins, gills, and scales

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Fish can be described as• Multicellular organisms• Organisms which live in fresh, salt

or brackish water• Heterotrophic• Having gills, fins and usually scales• Having jaws• Exhibiting a skeleton composed of

bone or cartilage

Skeleton

Fish may have an internal skeleton which consists of bone, cartilage, or a combination bone and cartilage

Jaws: true or lacking?

• True jaws are lacking in the photo of the fish seen here

• It is called a round-mouthed fish, or jawless

• Hagfish and lamprey are classified as Cyclostomata (round mouth) or Agnatha (jawless)

• Most fish have true jaws

Terminal and ventral mouths

• Mouth is considered ventral if located on the belly side of the fish

• If the mouth is located at the most forward region, it is terminal

Terminal mouth

Ventral mouth

Fins

• Single fins Dorsal

• Anterior• Adipose/Posterior

CaudalAnal

• Paired finsPectoral finsPelvic fins

Caudal fin

• The caudal fin (tail fin) vary tremendously among the fishes of the world.

• The two major types of caudal fins are– Homocercal- top and bottom half are

about the same– Heterocercal- top portion is much

larger than bottom half

Homocercal or heterocercal?

Observe each tail and identify the type

Bonnethead shark

Caudal Fin

• Fish with streamlined bodies and a stiff, crescent-shaped caudal fin or tail, tend to move rapidly through the water by swishing their tail from side to side.

Fish Scales

There are four types of scales with numerous variations of each kind:Placoid, cosmoid, ganoid and the most frequently encountered; cycloid andctenoid scales. Some fishes like sole have ctenoid scales on the 'eyed' side of their body and cycloid scales on the other side.

Fish ScalesScales and slime help to protect the fish from other

organisms

• There are four main kinds of scales, and numerous variations of each kind

1.Placoid 12.Cosmoid 3.Ganoid 24.Cycloid and Ctenoid 3 and 4

1 2 3 4

• Scales have a particular feature: they possess concentric patterns looking like the tree rings you can see on cut tree trunks. ...But scales are permanent on fish skin: they don't fall like tree leaves so they can to be used to calculate a fishes age. But fish growth can be irregular (e.g. females stop growing while reproducing...) and a laboratory study of each species is necessary to correlate the rings with real age. If you mount scales on a slide and look through them toward a light source, you can see some iridescence (rainbow colors) because light is diffracted light by the scale rings.

Ctenoid scales

Above: sole scale. 

Below: sea perch.

How old is a fish scale?

• As cycloid and ctenoid scales increase in size, growth rings called circuli become visible.

• By counting the annuli it is possible to estimate the age of the fish.

Other facts about scales

• Can a fish have more than one type of scale?

Yes. Some species of flatfishes (flounders, soles, etc) have ctenoid scales on the eyed side of the body and cycloid scales on the blind side.

• Can scale type vary with sex? Yes. In some species of flatfishes

(flounders, soles, etc) the males have ctenoid scales and the females have cycloid scales.

Body shapes of fish

Fusiform (torpedo-shaped)Depressed dorso-ventrally Compressed laterallyElongated, eel-likeGlobiform, spherically shapedTruncate

Fusiform

• Torpedo-shaped

Depressed

• Dorso-ventrally flattened

• Top to bottom

Elongate

• Eel-like, long bodyAlso,• Strong jaws• Muscular• Continuous fin

Compressed

• Laterally flattened • side to side

Globiform

• Spherical• Looks like a ball

Truncate

• Triangular

Markings and coloring of fish

• Counter-shading• Spotted• Striped• Banded• Barred• “See me”

Nurse Shark

• The upper surface of the body is yellow-brown to gray-brown. 

• The remainder of  body is a lighter shade of the same color. 

Striped

Hawaiian Squirrelfish

See Me!!

Pseudanthias hawaiiensis

photo courtesy of Richard L. Pyle

Barred

• Bands that stop and do not go all around

Identify these markings

Anatomy of a bony fish

More on anatomy

Food chain

• Some fish eat other fish…

• which ate smaller fish…

• which may have eaten tiny fish, microscopic animals or plants

Fish may be eaten by

• Other fish• Birds such as this

Osprey• Raccoons• Bears• Cats• Humans

Fish Behavior: School or not to school?

• Some fish prefer to live singly, while others travel in schools

• A school of fish may appear as one large animal to other animals

Where in the water do fish live?

Fish can be observed in all parts of the water column

at the surfaceopen water habitats - pelagicbenthic

www.dkonline.co.uk/animal/             

Blue Lined Triggerfish Pseudobalistes fuscus

• Beautiful, but very aggressive and very strong fish

• They are deep and fat bodied with enlarged heads

• They have very powerful jaws and can chew through just about anything

Puffer

Photo by ScubaMom 

Tetraodontidae: Puffer Fish

Body is cone-like with the widest end being the head, and the posterior tapering to the tail fin.

When threatened, inflates its body by taking in air and water.

Once “puffed,” it will float upside down until it can release the air.

By swelling the puffer becomes too large to consume.

Some Puffers also have small spines.Puffers have strong jaws and teeth fused into a

parrot-like beak.

Long Horned CowfishLactoria cornuta

Sturgeon

Orbiculate batfish Platax orbicularis Batfish are members of the Ephippidae

family.  Batfish are often recognized by their elongated fins, which are present in the younger stages.  In the growing process the fins become shorter and the body grows longer.   Batfish live in several different tropical and subtropical oceans around the world.  Juvenile Batfish stay in the inshore waters. The larger Batfish can be found on or near coral reefs.  Although age is a determining factor, some batfish can be found traveling in schools or as individuals.

Jawfish Opistognathus sp.

• Great aquarium community fish

• Male is a mouth breeder

Sargassum angler fish Histrio histrio

• Has its own fishing pole

• Not a strong swimmer

• Lives in floating Sargasso weed

Bonnethead shark

Blacktip shark

Thresher shark feed primarily on small schooling fishes (such as herrings, sardines) that are herded together with their tails and then stunned or killed with it.

Rays• Rays are dorso-ventrally

flattened• Distinguished by disk

shaped body, long-thick tail, and gills

body is composed of a disk (head, trunk and pectoral fins )

• The ventral side (underside) is the location of the mouth and five pairs of gill slits.

• Spiracles are the 1st gill slits and the only ones located on the dorsal side.

• Eyes are located dorsally

Atlantic Manta Manta birostris

• Plankton feeder• Become very

large

Southern stingray

Spotted gar Lepisosteus oculatus

Redfish

• The Redfish is notorious as a bottom feeding animal.

• It can also be seen on the surface, feeding on schools of fingerling baitfish. 

• It prefers shallow grass beds and structures where small fish and crustaceans are abundant. 

Red Snapper

• great eating• reef fish

Oyster Toadfish: Opsamus tau

• Bulging eyes • Fleshy flaps

(whiskers) on cheeks and jaw

• Skin is yellow to brown with dark brown oblique bars and brown reticulations

• Tail is long with tufted end. 

Oyster Toadfish Opsamus tau

Golden Butterfly fishChaetodon semilarvatus

• Pectoral fins are enlarged and wing like. 

• Dorsal fin located far to the rear of the body. 

• Thread shaped elongated rays on their pelvic fins, which function as tactile

• Tiger-like stripes

Golden Butterfly FishChaetodon semilarvatus

Sergeant - Major Fish Abudefduf saxatilis

• Grows up to 8"(20cm)TL 

• Lively colored • laterally

compressed • Black vertical

stripes narrow toward the belly*

• dark spot at the base of the pectoral fin 

• Small terminal mouth

*five black bars that resemble the insignia of that rank the insignia of that rank in military services

Scorpion fish:Stone fish• Body length: 10 to 20 “ • Weight: 1 to 5 lbs • Large head, mouth and

jaws, tapering to a small tail

• Color:  red, orange, yellow, and black. 

• Dorsal, pelvic, and anal fins have sharp spines with venom; venom glands lie alongside the spines. 

• Irregular surface and patchy colors hide the fish's body contours and make it look like a patch of weed-covered rock. 

Garibaldi Hypsypops rubicundus

• Orange in color • Small, narrow

mouth • Rounded,

somewhat oval shape. 

• Tail is short, and heart shaped 

• Stubby fins

Archer Fish Toxotes jaculatrix • The archer is capable of

leaping 12 inches out of the water and catch prey in its mouth.

• It can also launch a jet of water out of its mouth, to knock down bugs flying or walking on the plants above

• Lower lip protrudes over the upper

ARCHER FISH Toxotes jaculatrix

Pinfish

• Common in our Gulf this fish makes good bait!

Lookdown

Blackfin tuna

Silver Seatrout

Paddlefish Polyodon spathula

Its closest living relative, the more well-known sturgeon, the paddlefish is an ancient fish that has been cruising the rivers and tributaries of the Mississippi River system for hundreds of thousands of years

AKA in AL: Spoon-billed catfish

Pirana

Spanish Mackerel

Striped anchovy

Triple Tail

Gulf menhaeden

Littlehead porgy

Yellowfin tuna

White Marlin

Swordfish

Dolphin (male)

Jack Crevalle

Bigeye jacks

Atlantic bumper

Atlantic croaker

Atlantic spade fish

Cobia

Barracuda

Florida pompano

Gulf flounder

Starry Flounder Platichthys stellatus

• left-eyed flounder

White and striped mullet

Gafftopsail and hardtop catfish

Flathead catfish Pylodictis olivaris

• The barbels contain taste organs and thus in a sense are an extension of the tongue. 

• This is logical since the majority of catfishes are active at dusk and at night and need a supplementary organ to detect food (Grzimek 363).

Redtail Catfish Phractocephalus hemioliopterus

World record- 97lb 7oz , in wild 110 lbs and 3ft to 5ft

Symbiotic relationship

• Stoplight Parrotfish and Clown Wrasse

Seahorse

Creatures of the Deep-Mesopelagic

• Here's an up close and personal view of the wicked-looking Viper fish (Chauliodus macouni).

• Check out the teeth and the bug eyes on this guy!

Creature of the Mesopelagic depths

• A Fangtooth - scientists still aren't exactly sure why so many bony fishes of the deep have such enlarged, daggerlike teeth

Other deep ocean fish, the gulper eel

• Gulper eels have a hinged skull, which can rotate upward to swallow large prey. The gulper eel is particularly well-known for its impossibly large mouth

• Fish that live down here must adapt to a very low food supply, eating only "scraps" that sink down from above, or sometimes eating each other.

Bioluminescence is simply light produced by a chemical reactionIt

• The deep-sea fish Aristostomias has more than one light organ. The light produced by species like Malacosteus, Aristostomias, and Pachystomias has such long wavelengths that it is nearly infrared and is barely visible to a human eye. In addition, they can produce typical blue-green light from a separate organ.

(Illustration © Steven Haddock)

 T h e   B l a c k   D r a g o n f i s h

Interested in Reading…

• Creeps from the Deep : Life in the Deep Sea by Norbert Wu (Illustrator), Leighton R. Taylor

$10.46

Abyssal Zone

• Abyssal ZoneSome of the strangest creatures on our planet live in the deepest zone. The water here is pitch black, and almost freezing; the pressure is immense.

Deep-sea angler fish

Lantern fish

Light producing spots on their bodies that light up the dark surroundings

Shiny dots along the lower part of the body make light.

Bioluminescence, the making of light by organisms, is very common in deep water.

It serves many functions. Perhaps this fish uses light patterns as a means of recognizing its own kind in the dark.

Deep sea creature

Plastic pollution: Entanglement

• Six-pack rings cause problems for many organisms including birds, fish and mammals.

• Solution: cut them up before disposing

Fish Identification

To key a fishwww.amonline.net.a

u/fishes/ students/scales/

Interested in Fish???

Source of information

www.state.ia.us/.../fwb/fish/ programs/mgmt/surveys.htm

Sources

• Florida Fish and Wildlife Conservation

Commission http://floridaconservation.org • www.dkonline.co.uk/animal/ images

: www.heartlandhouse.com/images/

www.dkonline.co.uk/animal/ images

Lionfish Pterois volitans An extraordinary and

decorative fish, the lionfish is immediately identified by its long, fanlike pectoral fins, branched dorsal fin and brightly striped body. This eye-catching coloration warns potential enemies that the lionfish's grooved spines are equipped with potent venom, which can have serious, perhaps fatal, effects, even in humans.

Snakehead fish• http://abcnews.go.com/sections/scitech/DailyNews/

invasivefish020709.htmlhttp://abcnews.go.com/sections/scitech/DailyNews/invasivefish020709.html

A Fish Out of Water Reaching up to 40 inches in length and weighing up to 15 pounds, the formidable creature with snake-like scales on its head has an ability shared by only a few other species of fish — it can survive out of water.

http://abcnews.go.com/sections/scitech/DailyNews/invasivefish020709