Fish

Question 1

Heart

Answer 1

Fish have a 2-chambered heart that pumps blood in a single circuit: heart → gills → body → back to heart. Blood delivers oxygen and nutrients, and removes waste.

Question 2

Liver

Answer 2

The liver makes bile to break down fat, stores nutrients, removes old blood cells, balances blood chemicals, and helps remove nitrogen waste.

Question 3

Pyloric Caeca

Answer 3

Finger-like organs near the stomach; help digest food and absorb nutrients, though their exact function isn’t fully known.

Question 4

Gonads

Answer 4

Sex organs: testes (males) make sperm, ovaries (females) make eggs. Fertilization is usually external (spawning).

Question 5

Swim Bladder

Answer 5

Gas-filled sac that controls buoyancy.

Question 6

Stomach & Intestines

Answer 6

Digests food and absorbs nutrients.

Carnivores: short intestines
Herbivores: long intestines
Stomach contents reveal diet and help with bait choice.

Question 7

Kidneys

Answer 7

Filter waste and regulate salt and water balance. Let fish live in fresh, salt, or both types of water (e.g., salmon).

Question 8

Fins

Answer 8

Fins help fish move, steer, and balance.

Dorsal: defense & steering
Pectoral: balance & turn
Pelvic/Anal: steering & balance
Tail (Caudal): propulsion

Question 9

Gills

Answer 9

Gills, covered by an operculum, take in oxygen from water and release carbon dioxide. Some opercula have spines for defense.

Question 10

Lateral Line

Answer 10

A line of sensory holes under the scales that detects vibrations and helps fish sense movement in the water.

Question 11

Nares

Answer 11

Nose-like holes that allow fish to smell underwater. Some species have an excellent sense of smell (e.g., catfish, eels).

Question 12

Scales & Slime

Answer 12

Scales protect the body; the slime layer prevents infection. Handle fish carefully to avoid removing it.

Question 13

Body Shape & Tail

Answer 13

Body and tail shape reveal habitat and swimming ability. Forked tails = fast swimmers; rounded tails = good at turning.

Question 14

Mouth Types

Answer 14

Upward (Superior): eats above
Downward (Inferior): eats below
Mouth shape and size relate to diet and feeding behavior.

Question 15

Lungs

Answer 15

Gills

Question 16

Intestines

Answer 16

Intestines

Question 17

Stomach

Answer 17

Stomach

Question 18

Liver

Answer 18

Liver

Question 19

Ovaries/Testes

Answer 19

Gonads

Question 20

Ears

Answer 20

Lateral Line

Question 21

Skin

Answer 21

Scales & Slime

Question 22

Nose

Answer 22

Nares

Question 23

Arms

Answer 23

Pectoral Fins

Question 24

Legs

Answer 24

Pelvic Fins