The origami fish is an easy classical model
we begin with a square shaped sheet of paper
and fold diagonally
we fold our triangle into a smaller triangle
now we bring these edges aline
open the fold
now we fold this line to the corner
turn over
you can see how the corner touches the line
repeat with the other flap
this time you can fold the edges aline
fold this triangle up
and fold it inside
this will be a mauntain fold
and this will be a valley fold
just fold along your crease and push it inside
there are two layers
take the lower one an pull it down
I like to do it like so, not entirly out
so I get a symetric shape, but do as you like
you maybe this this crease
fold along it, edge to edge
be as precise as possible for a nice fish
repeat with the other flap
now there are two flaps
pull them in inside and backwords (inside reverse fold)
the shart line is intersected into 2 equal parts by the flap
this will result in a middle sized fin
repeat with the other flap
those triangles will be folde inside
just like triangle of the fin
just push it inside the body
and repead with all 4 triangles
the precreases make it easier, but are optional
for the fins on the side first fold like shown
open and fold the edge aline with the crease you just created
open and scaush fold like shown
and repeat on the other side
and that is your origami fish!
