Osteichthyes

The bony fish

Classification• Kingdom: Animalia

• Phylum: Chordata

• Subphylum: Vertebrata

• Class: Osteichthyes

• Examples: salmon, perch,

clown fish, puffer fish, tuna

TONS OF

DIVERSITY IN

BODY SHAPE,

SIZE AND

COLORATION!

Blob Fish

Mandarin gobi

Clown Fish

Puffer Fish

Angelfish

Flying fish

Gulper eel

Tripod fish

There are many unique adaptations from the basic

fish shape we are all familiar with.

Flounder

Halibut

Mola Mola

Some fish have flat body plans.

Box fish

Box fish

Longhorn cowfish

Some fish have more

boxy body plans.

Smooth Trunkfish

Blue boxfish

Hairy frogfish

Painted frogfish

Stone fish (Synanceia verrucosa)

Some fish are a bit

more random.

Hairy anglerfishWarty anglerfish

Wolftrap anglerfish

Monkfish

Deep sea anglerfishUnique

hunting

styles are

not

uncommon

in this

class.

Seahorse

Camouflage is very important to many species.

Seahorse camouflageBargibant’s pygmy seahorse

Frogfish camouflaging as a sponge

Flatfish camouflage

Seahorse

Camouflage is very important to many species.

Seahorse camouflageBargibant’s pygmy seahorse

Frogfish camouflaging as a sponge

Flatfish camouflage

Stonefish camouflage

Stonefish camouflage

Frogfish camouflage

Kelp fish camouflage

Oreo fish

Pineapple fish

Oreo fish

Lemon peel angelfish

Frillfin turkeyfish

Fish are friends,

not food?

Humuhumunukunukuapua a

A few of my favorites!

Leafy sea dragonMandarin goby

Parrot fish

General Lifestyle

• Range in size from tiny to huge.

– Largest bony fish is the Mola Mola or

Sunfish. It can reach 14 feet vertically and

10 feet horizontally and weigh over two tons.

General Lifestyle• Found in all types

of water: warm,

cold, salt, fresh

• Some fish migrate

hundreds or

thousands of miles

to spawn. We

think they locate

spawning grounds

by the smell.

Spawning• Catadromous

– Spawn in salt water, go to fresh water to

grow into adults, go back to salt water to

spawn (sturgeon)

Spawning

• Anadromous

– Spawn in fresh water, go to salt water to

grow into adults, go back to fresh water to

spawn (salmon, steelhead)

Spawning coho salmon Oceanic coho salmon

Coloration

• Look at the coloration of your fish. What

do you notice?

– Is it all the same color?

– Are there areas of light and dark?

– Why do you think they have this coloration?

General Lifestyle

• Many fish exhibit counter shading.

– Dark on dorsal side (top)

– Light on ventral side (bottom)

– Helps to protect them from predation, makes

them harder to see.

Be sure to color

in the fish on

your notes as

an example of

countershading.

General Lifestyle

• Exothermic (cold blooded)

– Body temperature is same as surrounding

environment.

– Some larger, fast moving fish like the tuna

have a primitive form of endothermy (warm

bloodedness).

Yellow Finned Tuna

Structure

• Endoskeleton made of bone

Tail Structure

• There are two major types of tail fin

(caudal fin) in fish. One is homocercal

and one is heterocercal.

• Look at your fish. Does it have a

homocercal or heterocercal caudal fin?

Tail Structure

Tail usually homocercal

in the bony fish.

(Cartilaginous fish like

sharks have heterocercal

tails.)

Blue parrot fish

Draw a representation of

these tails on your notes so

you can tell the difference.

Scales• Body covered with scales and mucus

– 1. Increases swimming efficiency

(decreases drag in the water).

– 2. Makes fish harder to catch.

• There are four

different types of

fish scales.

• Look at your

goldfish’s scales

closely. Can you

determine which

type of scale it

has? Hint: it is one

of these two.

• Goldfish have

cycloid scales.

Scales– 3. Three types of scales in the bony fish. (The other

type, placoid, is only found in the cartilaginous fish like

sharks.)

• A: ganoid (long nosed gar,

sea bass, “less evolved,

lower” fish)

• B: cycloid (carp, salmon)

• C: ctenoid (perch, bass,

“more evolved, higher” fish)

• Respiration is by gills via

diffusion.

• Gills are covered by a bony

covering called an operculum.

Gills

Operculum

• 1. Locate the operculum on your fish.

• 2. Watch your fish’s mouth and the

movement of the operculum.

– What correlation do you see between the two?

– What do you think is the function of the

operculum?

Lateral Line

• A row of sensory scales down each side

of the fish.

• Detects vibrations in the water.

Lateral Line

• Locate the lateral line on your fish.

GENTLY tap the side of the beaker.

Does your fish respond? He/she has

felt those vibrations with its lateral line.

Fins• Paired fins

– Exceptions: caudal fin, dorsal fin, and anal fin

– Sometimes the adipose fin is called a second

dorsal fin if it is large (some fish only have the

first dorsal fin).

1. Label the fins of the fish on your notes.

2.Locate the fins on your specimen.

Fin Function• Locate and name all the fins on your fish.

• Watch closely. Can you determine what

the function of each fin is? Some are

easier to determine than others.

___________fin: helps keep body upright

___________fin: provides forward motion

___________fin: helps keep body upright

___________fin: secondary fin that turns

left/right and backwards

___________fin: main fin that turns fish left/right

and moves fish backwards

Fin Function• Dorsal fin: helps keep body upright

• Caudal fin: provides forward motion

• Anal fin: helps keep body upright

• Pelvic fin: secondary fin that turns left/right

and backwards

• Pectoral fin: main fin that

turns fish left/right and

moves fish backwards

Notice how the fin is turned

differently depending on what

movement the fish wants to do.

Two types of finned fish

• 1--Lobed finned fish• Known only as a fossil until 1938

• Has paddle-like fins with a fleshy base

• Example: Coelacanth

Two types of finned fish

2. Ray finned fish

-Fins are supported by stiff rays and/or

bony spines.

-Most bony fish are in this group.

Lion fish

• Note the differences

in the pectoral fins of

the ray-finned fish

(left) and the lobed

fin fish (right)

• Many scientists

believe the lobed fin

fish are the ancient

ancestors of the early

amphibians.

Ray finned or lobed finned?

• Look at your fish. Is it a ray-finned fish

or a lobed fin fish?

Swim Bladder

• This is a bag of gas used for buoyancy

(to control depth).

• Almost all fish

have one. Those

that don’t, sink

if they stop

moving (sharks).

How a swim bladder works

• Decrease gas = fish goes down

• Increase gas = fish goes up

• Fish change gas

content by gulping

air or by diffusion

of gasses from

blood stream.

Please carefully return your fish to the lab

bench where you got it.