Be aware, this achievement is missable for different reasons:

According to GuilDer90 you need to be careful with reloading different saves. You *can* quit the game and reload a save game. However, you should not collect some bottles (let's say 1,2,3), then reload to before you collected them and then collect other bottles 4,5,6. That means 1,2,3 won't count toward the achievement and need to be done again on the same save after 4,5,6.

This is particularly important since you lose the ability to go fishing later in the game. So be sure to do this achievement as early as possible if you want to do it.

The locations are encoded according to the principle <field name on the map>-<fishing line colour>-<bait size>.
The fishing line colours used are R = red, G = green, B = blue. The bait sizes used are 1 = standard bait, 2 = small green fish.
Example: A1-R-1 means field A1, red fishing line, smallest bait

You only need baits 1 and 2 for all the bottles.

Huge thanks to @Conina for mentioning there were 4 locations missing, locations have been added.
Thanks to @GuilDer90 for checking whether a reload is needed.
Thanks to @FritzMatador and @Wolverous for mentioning a missing bottle.

(see below for community additions after I published the guide for the first time)

A1-R-2
A1-B-1
A1-G-1

A2-B-1
A2-G-2

A3-B-2
A3-G-1

A4-B-1
A4-B-2

A5-B-1
A5-B-2

B1-R-1

B2-R-2
B2-G-1

B3-R-1
B3-G-2

B4-R-1

B5-G-1
B5-G-2

C2-R-1
C2-B-2

C5-R-1
C5-B-2

D1-R-2

D2-G-1
D2-G-2

D3-B-1
D3-B-2

D4-G-2

D5-G-1
D5-G-2

E1-G-1

E4-B-2
E4-G-1

F1-R-1
F1-R-2
F1-G-2

F4-B-1
F4-G-2

F5-B-1
F5-G-2

G1-R-1

G2-R-1
G2-R-2

G3-R-1
G3-G-1
G3-G-2

G5-G-1

H2-B-1
H2-B-2

H3-B-1

H4-B-2
H4-G-1

I2-R-1

I3-B-1
I3-B-2

J2-B-1

J3-G-1

J4-B-1
J4-G-2

These ones were added thanks to @Conina:
C3-G-1
E5-B-1
E5-B-2
I4-R-1

added thanks to @FritzMatador and @Wolverous:
E4-R-1

(updated on 2025-05-16)