Perch are bony fish covered in thick scales that help them reduce friction and protect their soft tissues while swimming swiftly. They have two eyes without eyelids, four pairs of gills protected by an operculum that forces water over the gills, and five types of fins. Perch also possess a lateral line to detect pressure changes, internal organs accessed through a side window, and complex digestive, circulatory, and reproductive systems aided by a swim bladder for buoyancy.

2.  Perch are bony fish, they have an
endoskeleton made mostly of bone

3.  They are covered
in thick, keratin
heavy scales
 These help
reduce friction in
the water so fish
can swim quickly
 They also protect
soft tissue from
damage

4.  Most bony fish have two eyes without eyelids
 They do have a protective layer

5.  There are 4 pairs of gills, one on each side of
the head, and they are protected by an
operculum
 The operculum also force water over the gills
to help the fish breathe

6.  Similar to cartilaginous fish, bony fish have 5
different types of fins:
 Dorsal
 Pectoral
 Pelvic
 Anal
 Caudal

7.  Perch, like all fish possess a lateral line used
to detect pressure changes

8.  To reach the internal organs, a window is cut
on one side of the fish

9.  A perch has a complete digestive system, a
closed circulatory system, and a complete
reproductive system

10.  One major difference between bony and
cartilaginous fish is buoyancy
 Bony fish has a normal-sized liver, and
instead use a gas (swim) bladder to stay
afloat

11.  Perch have complex brains