2. General Fish Information
• Fish make up half of all vertebrates on Earth.
• 15, 300 marine species
• 9,000 freshwater species
• They first appeared more than 500 million years
ago.
• 3 groups of fish
1. Jawless – Class Agnatha
2. Cartilaginous – Class Chondrichthyes
3. Bony – Class Osteichthyes
• Fish – The term “fish” refers to a single
individual or more than one of the same species.
• Fishes – the term “fishes” refers to more than
one species of fish.
4. 3 Main Body Parts
2. Scales
• protection.
• Many species secrete a
protein-like “slime” that
contains natural antibiotics
to protect them from
disease.
• On many bony fish species
you can count the rings on
the scales to determine
age.
5. 3 Main Body Parts
3. Gills
• Oxygen exchange.
• in through the mouth
• out through the gills
• Oxygen passes out of
water into
bloodstream by
diffusion.
6. 1. Lamprey:
• Parasites
• Primarily freshwater fish –
breed in rivers and lakes and
some move to saltwater as
adults.
• Sucker-like mouth with horn-
like teeth
• Attach to fish and suck up
tissues and body fluids of host.
• Lampreys have an
anticoagulant in the saliva that
keeps the blood of the victim
fluid.
Jawless Fish – Class Agnatha
Lamprey
Lamprey Mouth
7. Jawless Fish – Class Agnatha
• Hagfish
• * no eyes, jaws, scales or
paired fins
• * worm-like body
• * 4-6 short tentacles around
the mouth
• * toothed tongue
• * scavengers or parasites of
slow moving fish
• * produce enormous amounts
of slime – 5 gal/min
• * The slime is a defense
mechanism. – slime cocoon
• * Uses a knot to get rid of
slime - also sneezes
Hagfish slime
Hagfish
