Fish Anatomy & Physiology
By: Karmyn Ruiz.
P.1
Fish Anatomy & Physiology
• Fins are appendages used by the fish to
maintain its position move, steer, and stop.
• Anal fins are on the lower side of the body
near the tail that lends stability in swimming.
• Pectoral fins are paired fins on either side of
the body that allow the fish to move side to
side.
Fish Anatomy & Physiology
Bony Fish Example:
• Caudal fin is the main
propelling fin.
• Pelvic fin is the pair fins on
the lower side of the body,
near the head.
• The first dorsal finis the
hardest fin on the side of
the body.
• The second dorsal fin is the
softer fin on the upper side
of the body.
Fish Anatomy & Physiology
• The eyes on a fish are the side organs located
on the head.
• Vision under water gives fish a small amount
of light available in all but the uppermost
layers of water.
• Nostrils in fish are used to detect odors in
water.
• Fish use their smell rather than sight to locate
food.
Fish Anatomy & Physiology
Bony Fish Example:
• The mouth of a fish is what
fish use to catch their food.
• Fish have a sense of taste
and may sample items to
taste them before
swallowing if they are not
obvious prey items.
• Fish may or may not have
teeth.
Fish Anatomy & Physiology
Mouth placement
Inferior
Superior
Fish Anatomy & Physiology
Fish anatomy is the study of the
form or morphology of fishes.
Fish physiology is the study of how
the component parts of fish
function together in the living fish.
Scale Types
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Placoid
Ganoid
Cycloid
Ctenoid
Placoid
• Placoid: Sharks and Rays have placoid scales.
• Placoid scales are tough scales that cover the
skin of elasmobranchs (sharks and Rays)
• Placoid scales are packed tightly together and
grow with their tips facing backwards.
Placoid
The function of these scales is to protect
the shark and rays from their predators.
Ganoid
• Ganoid scales are usually rhomboid in shape
and have articulating peg and socket between
them.
• Ganoid scales are found in fishes such as
bowfin, paddlefish, gar, and sturgeon.
Ganoid
Ganoid scales have a hard outer
layer that is cosminelike layer
and then a vascular bony layer
Cycloid
• Cycloid scales have a
smooth outer edge and are
found in soft rayed fish.
• Mostly in bony fishes.
• Cycloid scales exhibit a
smoothly rounded posterior
edge.
Ctenoid
• Ctenoid scales consiste of a rigid surface layer
primarily composed of calcium based salt and
a fibrous inner layer that is mainly made of
collagen.
Ctenoid